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# CERN Accelerating science

The Preprints collection aims to cover as far as possible all the grey literature in particle physics and its related technologies. The collection contains something like 400,000 documents, out of which about 50% can be accessed electronically. The documents originate from a variety of institutes all over the world. The collection, currently available, starts in 1979 and it has a full coverage of the arXiv.org e-Print archive since its beginning in 1991.

# Preprints

2016-02-14
07:50
 Elements of Linear Algebra. Lecture Notes / Cotaescu, Ion I These pedagogical lecture notes address to the students in theoretical physics for helping them to understand the mechanisms of the linear operators defined on finite-dimensional vector spaces equipped with definite or indefinite inner products. [...] arXiv:1602.03006. - 2016. - 44 p. Preprint

2016-02-13
21:25
 Search for R-parity violating decays of a top squark in proton-proton collisions at $\sqrt{s} =$ 8 TeV The results of a search for a supersymmetric partner of the top quark (top squark), pair-produced in proton-proton collisions at $\sqrt{s} =$ 8 TeV, are presented. [...] CERN-EP-2016-005 ; CMS-EXO-14-013-004. - 2016. Additional information for the analysis - CMS AuthorList - Fulltext

2016-02-13
10:01
 Combined search for anomalous pseudoscalar HVV couplings in VH production and H $\rightarrow$ VV decay A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (= W or Z) in a sample of proton-proton collision events corresponding to an integrated luminosity of 18.9 fb$^{-1}$ at a center-of-mass energy of 8 TeV is presented. [...] CERN-PH-EP-2015-331 ; CMS-HIG-14-035-003. - 2016. Additional information for the analysis - CMS AuthorList - Fulltext

2016-02-12
19:02
 Test of CP Invariance in vector-boson fusion production of the Higgs boson using the Optimal Observable method in the ditau decay channel with the ATLAS detector A test of CP invariance in Higgs boson production via vector-boson fusion using the method of the Optimal Observable is presented. [...] CERN-EP-2016-002. - 2016. Fulltext - Previous draft version

2016-02-12
08:44
 Observation of Spatiotemporal Chaos Induced by a Cavity Soliton in a Fiber Ring Resonator / <NAME> ; <NAME> ; <NAME> ; <NAME> ; <NAME> G We report on the experimental observation of temporal cavity soliton destabilization via spatiotemporal chaos in a coherently-driven optical fiber ring resonator. [...] arXiv:1602.03882. - 2016. Preprint

2016-02-12
08:44
 Coupled Wavepackets for Non-Adiabatic Molecular Dynamics: A Generalization of Gaussian Wavepacket Dynamics to Multiple Potential Energy Surfaces / White, Alexander ; Tretiak, Sergei ; <NAME> Accurate simulation of the non-adiabatic dynamics of molecules in excited electronic states is key to understanding molecular photo-physical processes. [...] arXiv:1602.03876. - 2016. - 6 p. Preprint

2016-02-12
08:44
 Electron heating via the self-excited plasma series resonance in geometrically symmetric multi-frequency capacitive plasmas / Schuengel, E ; <NAME> ; <NAME> ; <NAME> ; Derzsi, A ; Schulze, J The self-excitation of Plasma Series Resonance (PSR) oscillations plays an important role in the electron heating dynamics in Capacitively Coupled Radio Frequency (CCRF) plasmas. [...] arXiv:1602.03853. - 2016. Preprint

2016-02-12
08:44
 Automated Selection of Active Orbital Spaces / Stein, <NAME> ; Reiher, Markus One of the key challenges of quantum-chemical multi-configuration methods is the necessity to manually select orbitals for the active space. [...] arXiv:1602.03835. - 2016. - 29 p. Preprint

2016-02-12
08:44
 Bayesian Sparsity for Intractable Distributions / Ingraham, <NAME> ; Marks, Debora S Bayesian approaches for single-variable and group-structured sparsity outperform L1 regularization, but are challenging to apply to large, potentially intractable models. [...] arXiv:1602.03807. - 2016. Preprint

2016-02-12
08:44
 A multiscale model of distributed fracture and permeability in solids in all-round compression / De Bellis, <NAME> ; <NAME>, Gabriele ; Ortiz, Michael ; Pandolfi, Anna We present a microstructural model of permeability in fractured solids, where the fractures are described in terms of recursive families of parallel, equidistant cohesive faults. [...] arXiv:1602.03801. - 2016. - 22 p. Preprint

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## Encyclopedia > M A S H (television)

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# M A S H (television)

Inspired by the film of the same name, M*A*S*H (Mobile Army Surgical Hospital) was an American television series that aired on CBS from September 17, 1972 to February 28, 1983 (251 episodes). The sitcom was about an outfit of medical workers stationed in Korea during the Korean War. Much like the movie, it combined elements of a "zany" comedy and a darker antiwar message.

20th Century Fox head <NAME>[?] gave the show to producer <NAME>[?] and comedy writer <NAME>. This combining of genres was unusual for television series of its time, and was in fact an early example of what later became known as a dramedy[?]. The show's producers did not even want a laugh track in the show, but this proposal was rejected by CBS; however, as a compromise, the emergency room scenes were shown without a laugh track, and in fact the show was shown in the United Kingdom entirely without the use of canned laughter. The DVD release offers a choice between laugh-encrusted and laugh-free soundtracks. Many of the stories were based on real life tales told by hundreds of actual M*A*S*H surgeons interviewed for the show.

At the end of the its first season the show ended 46th in the ratings. CBS responded by moving the show to Saturday night between hits All in the Family and The Mary Tyler Moore Show. M*A*S*H ended the next 9 of 10 seasons in the top 10.

The series used the theme song "Suicide is Painless", which was taken from the film, though without the lyrics. Some said the series seemed to be more about the Vietnam War, given the attitudes of the characters, than about the Korean War -- despite its Korean setting. However, even the movie was somewhat anachronistic, given its use of such early seventies fashion as the fu manchu mustache. The show's producers have said that the movie was really about all wars, not just Korea or Vietnam.

The series was followed by After M*A*S*H[?] starting Morgan, Farr, and Christopher reunited in a midwestern hospital after the war. It was not well regarded, and was quickly cancelled.

The show featured <NAME>, who wrote and directed some of the most emotional and award winning episodes;

Out of all the starring characters Hawkeye, Hotlips, Klinger and <NAME> were the only ones in the show for its entire series. <NAME> left the show at the end of the third series, and his character <NAME> was discharged and sent home. In the final scene of his last episode it was reported that Blake's plane had been shot down and he was killed. Actor <NAME> left the series after the end of series three due to disagreements about his character. At the beginning of the fourth series Hawkeye was informed by Radar that Trapper had been discharged, and audiences did not see Trapper's departure. At the same time <NAME> was assigned to the unit as Commanding Officer replacing Blake, while BJ Hunnicut was drafted in as Trapper's replacement. <NAME> left during the first episode of series six as <NAME> became mad and was drafted away from the 4077th. <NAME>, a snobbish but highly skilled surgeon, was his replacement. A couple of episodes into series eight <NAME> left the series, and Radar was discharged. Existing character Klinger took over Radar's post, the character thereafter enjoying a more prominent position in the series.

<NAME> (Radar O'Reilly) was the only M*A*S*H actor to reprise his role from the movie, retaining his extraordinary ability to detect the arrival of choppers transporting wounded long before anyone else could hear a thing. When Burghoff left the series, the company clerk role was taken up by <NAME> (Corporal (later Sergeant) Klinger, whose cross-dressing never got him the discharge he wanted).

Viewed as one of the most popular sitcoms in history, it is still a very popular syndicated series. Originally seen as an ensemble show, it became increasingly centered around <NAME>'s character, <NAME>. The show survived many personnel changes over the course of the show, and in fact the series changed its tone over the years. Initially, the series placed more emphasis on the "zany" elements, while in the later years it focused more on serious elements and character development; however, both the serious and the comedic elements were present throughout the history of the series. In the later years the story lines began to also stale and the show's comedic edge had dulled even though the show was still in the top of the ratings. Alda and his fellow actors then voted to end the series with the 10th season but CBS and 20th Century Fox offered the actors a shortened 11th season leading up to an opportunity for them to say goodbye in a grand finale.

Goodbye, Farewell, and Amen The final episode was titled "Goodbye, Farewell, and Amen" and was first broadcasted on February 28, 1983. The episode was 2.5 hours long and was viewed by over 125 million Americans (77% of viewship that night) which made "Goodbye, Farewell, and Amen" the most watched television episode in history up to that time.

The finale started in the wanning days of the war with Hawkeye in a mental hospital who was finally driven over the edge by a bus ride gone terribly wrong. The bus passengers, who were refugees, were in danger of being discovered and executed by a North Korean patrol. Hawkeye scolds the refugees to be quiet but a baby begins to whimper and its mother responds by smothering the child. Hawkeye repressed this by replacing the memory of the baby with that of a small animal.

Dr. Winchester captured a rag-tag bunch of Chinese musicians who he teaches Wolfgang <NAME>'s "Quintet for Clarinet and Strings[?]" to them. However he later sees all the musicians killed and as a result views classical music as stained for him (classical music was his number one solace during the war).

Corporal Max Klinger, best known for constantly trying to be discharged via a Section 8[?], finally decides to stay in Korea to be with his new wife even though he finally got his release papers (along with most of the 4077).

The final and perhaps most memorable scene was between Hawkeye and BJ Hunnicut. Hunnicut was not able to say goodbye and Hawkeye mocked him for this failure. Both men lament that they will be on opposite sides of the country after they go home and conclude that they will probably never see each other again. They tearfully embrace for the last time and Hawkeye boards a helicopter and lifts off. Hunnicut rides off on a motorcycle and as the helicopter ascends Hawkeye sees a final message from his longtime friend spelt out with stones on the sandy soil, "GOODBYE."

• <NAME>, Stay Tuned: Television's Unforgettable Moments (Andrews McMeel Publishing; 2002) ISBN 0-7407-2693-5

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OpenStudy (anonymous):

Ehat is the volume of a sphere with radius 9 ft? Leave answers in terms of pi please.

5 years ago
hartnn (hartnn):

volume of sphere with radius r is $$\huge V=(4/3)\pi r^3$$ just put r = 9 here.

5 years ago
OpenStudy (anonymous):

Is it 108 pi ft to the third power?

5 years ago
hartnn (hartnn):

nopes, r^3 = 9^3 = 729 4/3 *729 = 972 so answer is 972 pi ft^3

5 years ago
OpenStudy (anonymous):

Do you know what I did wrong?

5 years ago
hartnn (hartnn):

how did u get 108 ?

5 years ago


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# 18.27 Life in a Computer

The idea of artificial life, or life in a computer, dates back to the middle of the 20th century, with the computing pioneers <NAME> and <NAME>. Back then, the state of the art in computers was a behemoth called ENIAC. It was the size of a small house, weighing thirty tons, consuming 200 kilowatts, and needing three full-time technicians to swap burned-out valves and resistors. But Turing and <NAME> imagined a time when computing would be cheap, easy and portable. Turing was a troubled genius who killed himself at the age of forty one. He invented the idea of an algorithm—a logical step-by-step procedure for solving a math problem in a finite number of steps—and the Turing test—the hypothetical situation where a computer mimics human responses well enough to be considered intelligent. <NAME>ann was a giant of mathematics and science who invented the processing architecture that’s still used in most modern computers.

Starting in the 1970’s, researchers in the new field of computer science explored another von Neumann creation: cellular automata. Imagine a single square that’s colored black or white, with each color representing on or off. Simple rules describe whether neighboring squares or cells turn black or white: any live (or black) cell with less than two neighbors dies (turns white) of loneliness, any live cell with three or more neighbors dies of crowding, any dead cell with three neighbors comes to life, and any live cell with two or three neighbors lives on unchanged.

It sounds too primitive to be interesting, yet <NAME> at the University of Cambridge found surprising depth to this black-and-white, pixellated world. Conway took the essential idea of cellular automata, most easily displayed as a one-dimensional horizontal sequence where evolution with time is shown vertically, and he animated it in two dimensions. His "Game of Life" features patterns that evolve and die, some growing like cancers, and others creating endlessly changing patterns. It looks like a hybrid of a laser light show and animated fractals. Conway saw beautiful "gliders" and "guns" that generate an endless stream of new patterns. Guns act like wires that transmit information, so guns can combine to form NOT and AND logic gates, the basis of all computation. It’s been proven that the Game of Life is as capable as any computer with unlimited memory. The Game of Life isn’t visually interesting enough to divert a young teenager for more than a few minutes but scientists became very excited about the patterns generated in the software. (In any video game, everything is preprogrammed; nothing happens that the programmers didn’t anticipate.) First, the patterns demonstrate emergence—complexity that derives from simple rules and a primitive starting point. Second, the patterns are self-organizing. Both attributes are central to biology.

<NAME>, the math prodigy who created the Mathematica software package, has taken the interpretation of cellular automata even further. He’s shown that cellular automata can be used to calculate transcendental or prime numbers, find quick solutions to differential equations, and generate behavior that is random on small scales yet predictable on large scales. This last attribute is striking because it mirrors the way the unpredictable quantum world maps into the well-behaved world of macroscopic objects. This world of tiny squares and simple rules can be used to show that there are axiom systems beyond those of traditional mathematics; in other words, the sum of the knowledge in all math textbooks is just a subset of all possible mathematics. If anyone imagines that these conclusions are caused by the particular properties of two-dimensional arrays of cells, Wolfram has an answer for them too. He shows that the same conclusions hold if there’s no grid (i.e. if a network of connections rather than fixed cells), if there are more than two dimensions, and if there are constraints instead of rules. The formalism has almost unlimited scope.

<NAME> is the pioneer that organized the first international conference on artificial life at Los Alamos in 1987. He’s one of only five resident faculty members at the Santa Fe Institute, a small think tank where physicists and computer scientists and economists rub shoulders. It was there that Langton articulated the reasons we should take the study and implications of artificial life seriously. He claims that it’s artificial only in terms of components, not emergent processes. In other words, he argues that if these artificial components are properly implemented, the processes they support are every bit as genuine as the natural processes they imitate. This is a big claim. Langton is takes <NAME>’s famous statement that "life is digital information" literally. He’s saying that if computational elements carry out the same functional role as biomolecules in natural living systems, they will be "alive" in the same way that natural organisms are alive. In other words, it’s the process that counts and not the substrate.

One way to think about artificial life is that it’s just made of different stuff than the life that evolved on Earth. Simplistically, the human genome is just three billion base pairs written in a four-letter alphabet—information equivalent to a encyclopedia that can fit on a CD. (Although this is just the tip of an iceberg of information coded in the myriad ways that proteins interact with each other and the environment.) By analogy, the brain is just an electrical network of 100 billion neurons and a thousand trillion connections that works at a few kHz. If Moore’s Law—the doubling of computer power and data density every 18 months—continues unabated, computers will have this capability in 2020.


text: 2 what is velocity of ground with respect to b. These require the relative velocity of spaceship B with respect to A, which we first find using Lorentz velocity addition: 2 B A A B 2 c v v 1 v v u' c v 1 u' v u + + = + + = where u = velocity of. If two bodies are moving in the same direction at the same velocity, then the relative velocity will . has a known velocity in the frame of (with respect to) a medium like air or water which itself is moving with respect to the stationary ground; we can then ﬁnd the velocity of the plane or boat with respect to the ground from the vector sum in Eq. Acceleration and speed are constant but velocity …. Learn about the benefits of vitamin B supplements and why you should take them for better health. Question 1044696: A football is kicked at an angle of 37 degrees with a velocity of 20 m/s. to hit the ground? (b) If the plane has an air speed of 8 km/h, what is the horizontal distance that the wheel travels before it hits the ground. Given the formula for the orbital velocity, v = 2πr Torbit = r gR2 e r a rate of coverage can be calculated by rate of coverage = v · Re r ·w where w is the swath width (see also Figure 2). In simpler terms, this can be the vector sum of the velocities. In (c), let the velocity of the monkey with respect to ground be vM. 5o(with respect to a line perpendicular to the shore) in order to travel directly across the stream. (a) Derive a formula for the horizontal range R of a projectile in terms of its initial velocity …. A turtle is moving on the cart at 3. we conclude that the instantaneous velocity at t=a is 2 a. the velocity is non-zero, but the acceleration is zero 10. How high above the ground will it be. 00 s, the velocity of the mailbag is. The graph following represents the relation-ship between velocity and time for an object moving in a straight line. 5 km apart, how long will it be before they reach each other? (See Fig. v is the vertical velocity in meters/second (m/s) or feet/second (ft/s); g is the acceleration due to gravity (9. It then turns abruptly and gallops halfway back in 4. A ball is thrown vertically upwards at 19. A tennis ball is thrown from ground level with velocity vo directed 30° above the horizontal. You are driving home from school steadily at 65 mph for 130 miles. Since the person is walking west, in the negative direction, we write her velocity with respect to the train as v → P T = −2 m/s i ^. 0 $$\hat{k}$$ m/s, and the velocity of reference frame B with respect to C is 2. It's not actually moving with respect to the ground…. ground, the resultant velocity is the bird's velocity relative to the ground b v a a v g b v g respect to the water. 99 In Aguila 22LR 30 gr Copper Plated HP Brass Supermaximum Hyper Velocity …. Whether we are driving a car, riding a bike, or throwing a ball, we have an intuitive sense that a moving object has a velocity at any given moment -- a number that measures how fast the object is moving right now. Given, Initial velocity of the truck, u = 0Acceleration, a = 2 m/s2Time, t = 10 sa) According to the equation of motion, we have v = u + at = 0 + 2x10 = 20 m/sThe final velocity of the truck and hence, of the stone is 20 m/s. e the car Bappers to A to move with a speed 40 ms-1 from opposite direction. 28 Consider two trains A and B moving along parallel tracks with the same velocity in the same direction. The velocity at B is given as : (drB/dt) = (drA/dt) + (drB/A/dt)or vB = vA + vB/A RELATIVE MOTION ANALYSIS: VELOCITY = + Since the body is taken as rotating about A, vB/A = drB/A/dt = ωx rB/A Here ωwill only have a k component since the axis of rotation is perpendicular to the plane of translation. → is the velocity of the Man relative to the Train, v → T ∣ E {\displaystyle {\vec {v}}_{T\mid E}} is the velocity of the T rain relative to E arth. 29 Vector diagram for Equation 4. 81 m/s 2 (or or 32 ft/s 2) for every second it experiences. Putting these together, you can find the velocity of the man with respect to the ground. Using the Pythagorean theorem, the resultant velocity can be calculated as, R 2 = (100 km/hr) 2 + (25 km/hr) 2 R 2 = 10 000 km 2 /hr 2 + 625 km 2 /hr 2. Applying cosine Rule in the velocity diagram triangle: VB 2 2= 1. A shopping cart given an initial velocity of 2. The relative motion is calculated as: (4. E) increase the amplitude of the wave by a factor of 2. A falling object is acted on by the force of gravity: -9. A motorboat whose speed in still water is 3. 0 m/s undergoes a constant acceleration of 3. Part iGravitational Potential Energy (GPE) = mass x gravitational acceleration constant x heightGPE = 2 x 9. 2), the velocity of airplane A with respect …. (d) moving with uniform velocity…. Each has a speed of with respect to the ground. A swimmer starts from point A and reaches at point B after 2 s. As always you can ignore air resistance. So subbing back into the position equation (2) you can get the time it takes the ball to go from its highest point to its lowest point. Using the Law of Addition of Velocities, Equation (11. If the coefficient of kinetic friction between the log and the ramp is 0. velocity of the observer moving along in airplane B with respect to an observer at rest on the ground is just the velocity of airplane B and is given by V = v. The velocity of the car with respect to Earth is →v CE =80km/h^i. speed of 80KMph while car B is moving at a speed 50KMph in the same direction, find the magnitude and direction of (a) the relative velocity of car A with respect to B (b) The relative velocity of car B with respect to A. (b) The displacement of the mailbag after 2. At t = 11 s, the horizontal component (vx) of velocity, in the absence of air resistance, remains unchanged. Use the general function for a projectile to write a function that shows the height in feet of her golf ball as a function of time. You are on an airplane traveling 30° south of. Two friends, Barbara and Neil, are out rollerblading. Compute its velocity and acceleration as functions of t t t. (15) with respect to and setting it equal to zero: or Ground Lift Coefficient for Minimum Takeoff Ground Run Distance (16) Example 2. (c) the velocity of the object between t = 70 s and t = 90 s. The river is flowing at a speed of 2 m/s (with respect to ground), so the magnitude of the velocity of the duck with respect to ground can be found using the Pythagorean theorem, which is then V = (1. If it instead flies into a 10 km/h headwind, its ground speed is. 9) The velocity of rocket with respect to ground is v1 and velocity of gases ejecting from rocket with respect to ground is v2. Solution - 2 Horizontal and vertical components of velociy are independent to each other. What is the child’s velocity with respect to the ground? a) 5 km/h “upstream” b) 1 km/h “downstream” 2) A person walks up a stalled 15-m-long escalator. 29, we can solve easily for the magnitude of the velocity of the plane with respect to the ground and the angle of the plane's heading, θ. An airplane B flies to the south with a velocity of 500 m/s beside airplane A. The velocity of the air with respect to the ground is 40 m/s at an angle of 30° west of due north. a) The relative velocity to the airplane A respect airplane B. 0 m/s [E] and a boat on the river has a velocity of 7. A tennis ball is thrown off a cliff 10 m above the ground …. Therefore, cart B appears to move from South to North with a speed of 70 ms-1 for any person sitting in cart A. What is the resultant direction (angle) of the cannon ball (relative to a . An import ant concept emerges from the analysis of the two example problems above. 50 s for a rock thrown straight down with an initial velocity of 14. The velocity of the emitter particle relative to the scientist is _____ a) 0. Gravity doesn't have a horizontal component, and so (unlike the. Four out of five sources stated a value between 53 m/s and 56 …. D) increase the amplitude of the wave by a factor of 8. If you throw the ball upward with a speed of 9. Any point on such a graph will have coordinates (t,v), in which v is the velocity after a time t. 5 (B) x = 1 both C1 and C2 will move with respect to the ground (B…. Velocity of contact point Find a general expression for the velocity of the point of contact. Let t ∗ be the time at which the ball hits the ground. Answer: (a) 13 m/s2; (b) eastward; (c) 13 m/s2; (d) eastward вЂў70A boat is traveling upstream in the positive direction of an x axis at 14 km/h with respect to the water of a river. A wind is blowing with the bearing of 200°at 80 mph. If B is increasing its speed by 1200 mi/{ h }^{ 2 }, while A maintains a constant speed, determine the velocity and acceleration of B with respect to A. An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. Draw the position and velocity vectors for relative motion. The acceleration of the particle at the end of 2 seconds. Airspeed = Ground Speed (80) - Wind Speed (-20) = 100 mph. In the Earth frame rocket 2 is moving with velocity -v 2 i. 2JPart iiConservation of energy states that the sum of the GPE and KE at the intial position is equal to the sum of the GPE and KE at the final position. In the first case let us suppose two cars A and B are moving in the same direction with equal velocities (Va = Vb). The gradient of a velocity-time graph is acceleration 10 5-5-10 v (ms ) t (s) 0. Similarly, we can reverse which plate is being held fixed and hold plate B fixed. Car A is moving at a speed of 80 km/h while car B is moving at a speed 50 km/h in the opposite direction, find the magnitude and direction of A- the relative velocity of car A with respect to B B- the relative velocity of car B with respect to A. Graphing motion virtual lab 2 answers. A plane flying horizontally above Earth’s surface at 100. From the geometry in Figure, we can solve easily for the magnitude of the velocity of the plane with respect to the ground …. () dv dt v(t) v t a dt dv v t v 9. The gradient of a displacement-time graph is velocity 2. Electrical conductors allow electrons to flow between the atoms of that material with drift velocity in the conduction band. As you walk toward the back of your train at 3. The ball was hit with an initial vertical velocity of 130 feet per second. In general, with two reference frames (Say A and B) then you (or I) can say:. 2) Maximum or minimum velocity and corresponding displacement and time at which velocity …. The vector equation is →v PG = →v PA + →v AG, v → PG = v → PA + v → AG, where P = plane, A = air, and G = ground. A particle ( A ) is projected from the ground with an initial velocity of ( 10 mathrm{m} / mathrm{s} ) at an angle of ( 60^{circ} ) with horizontal. You are on an airplane traveling 30° south o…. Velocity of a Falling Object: v = g*t. Upon contact with the bat the ball is 1. velocity of 100 m/s and another object with an initial velocity of 10 m/s. Velocity is a measure of the speed and direction of the precipitation toward or away from the radar. In Example 1, the time to cross the 80-meter wide river (when moving 4 m/s) was 20 seconds. Find the flight time of the cannonball from its firing point to the point where it hits the ground. Rocket taking off from the ground The chemicals inside the rocket burn and produce very high velocity …. Car A has a velocity of +10 m/ s, car B has a velocity Of —10 m/ s. A motorboat, which has a speed of 5 meters per second in still water, is headed east as it crosses a river flowing south at 3. A ball is thrown horizontally from a point 100 m above the ground with a speed of 20 m/s. The magnitude of the average velocity is : a) 3. Week 1: Introduction; Lesson 1: 1D Kinematics - Position and Velocity. 1 nor C 2 will move with respect to the ground (C) C. A ball is thrown vertically upward with a velocity of 25 m s. The low velocities of ground-water flow can have important implications, particularly in relation . Velocity of a falling object as a function of time or displacement. (a) Briefly describe the motion of the beam represented by AB, BC, CD and DE. the x-velocity is non-zero, but the y-velocity is zero d. A car goes 78 m to the righty and then 22 m to the left. The velocity of B after collision is 6 m/s opposite to its direction of motion before collision. D) What is the angle below the horizontal of the velocity of the puck just before it hits the ground? A) 77. 20 N in the direction opposite to the velocity (B) 30 N in the direction opposite to the velocity …. the relative velocity of the ground with respect to B? c. Answer C is wrong because the distance increases every second. To find the relative velocity of train. A golf ball is struck with a five iron on level ground. average velocity = 30 1/2 - 1/2 average velocity of the balloon between t = 0 and t = 30 = 30 ft/sec c) Velocity is the change of displacement of a body with respect to time. Thus, any projectile that has an initial vertical velocity of 21. A proton moves in a uniform magnetic field B with a speed of 10 7 m/s and experiences an acceleration of 2 x 10 13 m/s 2 in the +X-direction when its velocity …. 1 will move but C 2 will be stationary with respect to the ground (D) C. I'm trying to buy 5,000 rounds or so of standard velocity. Now, what if you take out your instruments for measuring velocity or you see a change in, you see what the displacement is over a certain time for the. Where: α is the angular acceleration of the wheel (in radians/s 2), with respect to ground w is the angular velocity of the wheel (in radians/s), with respect to ground r is the radius of the wheel V o is the horizontal velocity of the geometric center O of the wheel, with respect to ground a o is the horizontal acceleration of the geometric. How much time will pass before the ball hits the ground? Base your answers to questions 17 and 18 on the following information. 1) that the velocity v is proportional to the square root of i. Now, you already know the direction of the angular velocity vector and, if angular velocity changes, there is an angular acceleration which is defined as a=[w 2-w 1]/Dt where w 2 is the angular velocity at the end of the time interval Dt and w 1 is the angular velocity …. platform jumps off the platform with a velocity v with respect to the ground. 1 to 2 months: Sausage, purchased frozen: After cooking, 3-4 days: 1-2 months from date of purchase: Hamburger, ground meats and ground poultry: Hamburger, ground …. Science for Class 10 Math/rs aggarwal 2018. 0 km/h with respect to the boat. What is the acceleration of a baseball thrown to the air at an angle of 45 degrees with respect to the horizontal as it returns to the ground? A. The terminal velocity for a skydiver was found to be in a range from 53 m/s to 76 m/s. Two parallel rail tracks run north - south. Vitamin B supplements are available in many forms. The 250-lb concrete block A is released from rest in the position shown and pulls the 400-lb log up the 30° ramp. 24) A transverse wave traveling along a string transports energy at a rate r. 57 5 5 gold badges 9 9 silver badges 20 20 bronze badges $\endgroup$ 1. The motion of the riverboat can be divided into two simultaneous parts - a motion in the direction straight across the river and a motion in the downstream . The bus begins moving 3 m/s east with respect to the ground. (round to nearest whole number) 252 m/s. At t = 0, it’s 30 inches above the ground, and after 4 seconds, it’s at height of 18 inches. 57 m/s b)x=theta =tan… View the full answer Transcribed image text : A cannonball is shot (from ground level) with an initial horizontal velocity of 37 m/s and an initial vertical velocity of 23 m/s. Horizontal component of the velocity at point C is v 0 cosθ C. Whereas the product of mass and acceleration gives the value of applied force on the object. 20? Assume pulley to be frictionless. PSI AP Physics C Kinematics 2D Multiple Choice Questions. the speed of the combined mass immediately after the collision with respect to an observer on the ground …. The relative velocity to the aircraft A respect aircraft B will be 850 m s^ {-1}. (b) moving with no acceleration. The two measurements necessary for calculating average speed are. #underbrace(v_"top"^2)_(color(blue)("=0")) = v_i^2 - 2 …. When using the relative velocity …. Here's how to win: Enter in 3⃣ ways (choose any or all for more chances to win): 1⃣ Like this post, tag 2 …. What is the speed of the plane with respect to the ground? (a) 154 m/s (b) 185 m/s (c) 188 m/s. Vertical velocity can be expressed as Vy - g * t. v = Final velocity in the y-direction which is zero for maximum height = 0. "The condition of equilibrium or motion of a rigid body remains unchanged if a force acting at a given point of the rigid body is replaced by a force of same magnitude and direction, but acting at a different point provided that the two forces have the same line of action". From this we see that when an object is lifted, like the suitcase in our example, it gains potential energy. The earth rotates once every 23 hours, 56 minutes and …. (b) The flea's trajectory must be a parabola as shown. Now, using the formula for relative velocity, V_ {AB} = V_ {A}– V_ {B} = 350 – 500. 5 meters/second in the same direction as the boat. Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of 10 ms -1 It implies that the boy is. 113, the relative velocity of the ground with respect to B will be: (a) 40 ms (towards . Three blocks shown in move vertically with constant velocities The relative velocity of w. Muon Decay: Time Dilation (\Moving Clocks Run Slow") Problem 1. A ball is kick with an initial velocity of 4 m/s at an angle of 12 degrees with respect to horizontal. Marilyn hit a golf ball on the ground with her driver. Solve any question of Motion in a Straight Line with:- Patterns of problems > Was this answer helpful? 0 0. Put into words, the velocity of A with respect …. This plane has a velocity with respect to the wind. Example 4: An object is projected upward from ground level with an initial velocity of 112 ft/sec. The velocity of A with respect to B will be (g = 10 m/s2) : (A) zero (B) 1 m/s (C) 2 m/s (D) None of these Q. The velocity of reference frame A with respect to reference frame B is 4. calculate the time it takes the ball to hit the ground. Since the acceleration is acting in the downward direction and the velocity is actin. b) An airplane is flying on a compass heading (bearing) of 170° at 460 mph. Horizontal velocity is equal to Vx. Light in vacuum always travels at the same speed c, exactly 299,792,458 meters per second, no matter how it is created or in what frame it is observed. The ball is caught by the receiver 2. (b) What angle does the shortest distance make with respect to due east? Shortest distance = length of hypotenuse of triangle = √{37 2 + 29 2} = 47. There is a wind blowing at 85 km/h to the northeast. 81 m/s^2) or 32 feet per second per second (32 ft/s^2), regardless of mass. Vertical component of velocity is U …. 5 x m x v 2)As the mass is released from rest the initial velocity …. find the magnitude of average velocity …. If it was thrown horizontally or dropped, and hit the ground 3. The really simple way to get #3 is to start from a frame of reference tied to the axle. 0 m/s due north relative to the air mass, while its velocity relative to the ground (its total velocity) is 38. The motion of a particle moving in straight line is given by a relation. Its height above the ground, as a function of time, is given by the function, where t is in seconds and H ( t) is in inches. The velocity of the particle at the end of 2 seconds. v_pg: sqrt(v_pg_x^2+v_pg_y^2); (%o10) 114. After time t,it return back towards the origin with the speed 2v and reaches the origin in t/2 sec. On the other hand, acceleration is the rate of change of velocity with respect to time. To a passenger in train A, the train B will appear to move westwards with a …. What is the moment of inertia of the thigh with respect …. I'm not sure how to find the velocity though. 9 2 2 u x (5) Given that u = 7, OA = R m and the maximum vertical height of P above the ground is H m, (b) using the result in part (a), or otherwise, find, in terms of c, (i) R (ii) H. Experiment 2 – Free Fall and Projectile Motion. The rate of coverage is measured in area covered per unit time. A 75 kg skier starts from rest and slides down. So the relative velocity of the man with respect to the ground is 515 mph. 5, determine the velocity of the block as it hits the ground at B. 8 metres per second squared (m/s 2). An icon used to represent a menu that can be toggled by interacting with this icon. Ue4 character physics collision. PDF AE 245 homework #2 solutions. 81 meters per second per second (9. Note that you subtract the velocity of the fixed plate from the moving plate. Gravity causes an object to fall toward the ground at a faster and faster velocity the longer the object falls. Therefore, regardless of the which plate is held fixed (the reference frame), the relative velocity between to plate is always just the difference in the velocity of the two plates (expressed in the same reference frame). 6 Problem-Solving Basics for One-Dimensional Kinematics, is a simple one-dimensional type of projectile motion in which there is no horizontal. Apply integration on each side with t. 0 m//s with respect to the water In a direction perpe asked …. Calculate: a) The relative velocity to the airplane A respect airplane B. Using s = ut + at 2 /2 for change in vertical distance in time t, with acceleration a (-9. Find the velocity of swimmer with respect to river. 81m s 0 0 2 0 relative velocity of B with respect …. You know that your ball is being thrown from a height of 3. The relative velocity of B with respect to. The acceleration along the ground is the same, so at 5000 feet down the runway, the ground speed is again 80 mph. 8 m/s, Dy=h=15 m, and v 1=0 yields t = 2 h g = 2*15 m 9. If i ignore someone on messenger can they see my story. In mathematics, an argument (also known as input) of a function is a value that must be provided to obtain the function's result. One pin is still standing, and Jeanne hits it head-on with a velocity of 9. Find the velocity of the rain with respect to (a) the car and (b) the Earth. Analyze one-dimensional and two-dimensional relative motion problems using the position and velocity vector equations. The birds are not touching the ground or anything in contact with the ground…. When does the ball strike the ground? b)What is the velocity of the ball when it strikes the ground? arrow_forward. Calling east the positive direction, you know the velocity of the train with respect to the ground (vTG=60 m/s). 2 Distance, Velocity, Acceleration. That is the resultant of the two vectors, that is velocity of the sheep 4m/s and the velocity of the lion 3m/s comes out to be . The magnitude of the aircraft velocity with respect to the ground axes is the same as the air speed for a stationary atmosphere; thus, Va = g =Va w 151: 33 m s(2) while the x-component of the aircraft velocity with respect to the ground (or ground speed) is Vx = ucosθ + wsinθ =(150cos10 20sin10) m s 151: 19 m s(3) 1. is the change in position of an object: where. To begin, subtract 15 from both sides of the equation giving -4. Putting these values in third equation of motion v 2 = u 2 + 2 a s we have. With these changes, equation (1. To find velocity, we take the derivative of the original position equation. A ball is dropped from a height of 80cm after each bounce. Inputs: First, hit the “distance covered” tab. What happened to <NAME>. Mechanics))Lecture)4,)Slide)6 v belt,ground = 2 m/s v dog,belt = 8 m/s A))6 m/s)) B))8 m/s)) C))10 m/s CheckPoint A"girl"stands"on"amoving"sidewalk"thatmoves"to"the"rightat 2 m/s" relave"to"the"ground. Consider the movement of the earth's surface with respect to the planet's center. A football is kicked at an angle θ with respect to the horizontal. If we drop it from rest, it will be going 10 m/s downward in 1 second, 20 m/s downward in 2 …. One of the most common complaints from Honda owners is a persistent "check TPMS" warning light. 95 X 10 8m/s 16 In a uniform circular motion a. Where the following additional variables are introduced: V rel is the horizontal velocity of point P (on the wheel) relative to point O a rel is the horizontal acceleration of point P (on the wheel) relative to point O Therefore, by vector addition the velocity of point P with respect to the surface/ground …. The average velocity of a particle is the rate of change of its position with respect to time. First, set up your equation to get ready to find a derivative: x (t) = 4t 2 + 4t + 4. the baseball’s initial velocity is 12. a long jumper leaves the ground at an angle of 30 degrees to the horizontal at a speed of 6 m/s. Science Physics College Physics (a) Calculate the height of a cliff if it takes 2. Find out the benefits of B vitamins. Find the velocity of Air Force One with respect to the ground. Linear velocity is measured in linear units divided my time units, such as meters per second. (a) How high above the edge of the cliff does the rock rise? (b…. The roadway of this bridge is 70. Find (a) the magnitude and (b) the direction of magnetic force on the proton. There are three primary types of hepatitis. Velocity is nothing but the rate of change of displacement. velocity and the translational velocity of a point on a rotating object: v = R w • vcm is the velocity of the center of mass with respect to the ground for the rolling motion. Here, we have considered the velocity of the aircraft B as positive because it flies in the same direction of the aircraft A. In part (b), the initial velocity is 260 m/s horizontal relative to the Earth and gravity is vertical, so this motion is a projectile motion. Since there is no slipping, point A has zero velocity. How far has the ball fallen after 2. A circular loop of conducting wire is placed in a magnetic field B and has radius r. 0131571354815 Answer: (a) 114 m/s. When we break any diagonal vector into two perpendicular components, the total vector and its components— —form a right triangle. The above 3 formulas are used for solving problems involving distance, velocity and time. b) Find the actual ground speed and direction. It explains the concept of the frame of reference and how it's used to determine the relative velocity of an object with another regardless if . Velocity provides information. ) When will the ball hit the ground below? d. A gunman and an apple are both at height 98 m above the ground, at distance 200 m from each other. And finally we're given the information that the plane, the velocity of the plane, the magnitude of the loss of a planet with respect to air as 70 kilometers per hour. The concept of relative velocity applies to two objects. How high is the javelin off the ground after 2. Assessing velocities involves vector addition and a useful approach to such relative velocity problems is to think of one reference frame as an "intermediate" reference frame in the form:. Relative velocity of A with respect to B , i. What is the new angular velocity of the platform? (A) ( +2 )𝜔𝑅−2 𝑣 𝑅 (B) ( −2 )𝜔𝑅−2 𝑣 𝑅 (C) ( +2 )𝜔𝑅+2 𝑣 𝑅 (D) ( +2 )𝜔𝑅−2 𝑣 𝑅 (E) ( +2 )𝜔𝑅−2 𝑣. In our example there will be two moving walkways going in opposite directions, both at a speed of 1. Final velocity (v) = 100 km/s = 100 x 103 m/s. (B) The coefficient of restitution is 0. Vbc is the velocity of object B with respect to reference frame C in distance/time units. It was carefully engineered to provide excellent performance when properly operated and maintained. t 2 A golfer hits a ball from horizontal ground, giving it an initial velocity of 40 m s–1 at an angle of 27 to the horizontal. 0 km/h with respect to the ground. The loop is spinning in the magnetic field at an angular velocity of 𝜔 with respect to its diameter. Again we will use one motion equation with initial velocity considered as zero(at height h velocity was zero) V f 2 = 2gh So KE at the ground level C is =(1/2)m V f 2 = (1/2)m 2gh=mgh. t = v Image and object both are moving towards each other so relative velocity …. velocity of person relative to the ground velocity of person relative to the train velocity of train relative to the ground 58. t ground = v Velocity of the image in the mirror w. What is the resultant velocity of the airplane with respect to the ground?. 2 x 10 7 m/s enters the laboratory moving horizontally from south to north. Velocity of a monkey running on the roof of a train A against its motion (with a velocity of 18 km per hour with respect to train A) as observed by a man standing on the ground. A skateboarder shoots off a ramp with a velocity of 6. Find the time when it reaches the ground. A small ball falling vertically down with velocity 2 m/s strikee elastically an inclined plane moving with velocity 2 m/s. Square the velocity and then multiply all of the variables together. The river water is moving with a velocity …. (b) velocity of boat with respect to water. Vst=Vs-Vt => Vst=2- (-50) <=> Vst=2+50 <=> Vst=52. 5% of total body mass, and the length of the thigh is 23. If the only force considered is that attributed to the acceleration due to gravity, find Integrate the following with respect …. 2)If you walk west toward the back of the train, with a speed of 3. S&B 9mm NATO 124gr FMJ White Box 50rd box $27. Example Find the velocity of L with respect …. In the simplest kind of projectile motion problems, there is no initial velocity. Find the acceleration of the rocket 3 seconds after being fired. Most people find relative velocity to be a relatively difficult concept. Now while calculating the difference between V1 and V2, we will use the vector addition process but with a tweak. Since the person is walking west, in the negative direction, we write her velocity with respect to the train as. The rocket hits the ground at height h = 0. Speed of point d: This is the same speed as that of point b, 2 v 0. Determine: a) the time of flight (5) b) the range of the projectile (5) c) the maximum height above the ground (5) d) the components of vx and vy when the projectile strikes the ground (5) e) the magnitude of the velocity and angle the velocity vector makes with respect to the ground just as the projectile lands (10). Find the velocity of the ant with respect to the: A)boat B)water. An onlooker is moving at a speed of -25m/s with respect to the. Rolling, Torque, and Angular Momentum. The average velocity that the car traveled was 14. It describes the velocity of an object with respect to the other object at rest . Raindrops are falling at a constant speed vertically with respect to the Farth. 30 km with a constant velocity of 165 m/s west. V B A = V B − V A V B A = 90 − ( − 54) = 144 k m h − 1. What are the north and east components of this displacement? 3. Relative velocity of ground with respect to B = 0 − vB = 25 m s^−1. A car accelerates from rest and reaches a velocity of 6 ms after 2 seconds. The relative velocity of B with respect to A, V BA = 80 km h −1 due west. Once the instantaneous center is located, the velocity of any other point in the body can be determined using relative velocity. If you're riding in a train moving at 10 m/s east, this velocity is . State the domain and range of r =710cos+ θ. Velocity of the Vg = -1500 + 500 = -1000km/hr. (2) that '1 + 2=2 (9) and from Eq. At a certain instant, a point P on its rim has a velocity whose x and y component are 120 in. The plane is known to be moving at 45. Answer (1 of 7): First, permit me to rephrase the question more precisely. The instantaneous velocity of an object is the limit of the average velocity as the elapsed time approaches zero, or the derivative of x with respect to t: v(t) = d dtx(t). (II) Two locomotives approach each other on parallel tracks. The velocity of the current in a river is 10. t C is 100m//s upward and the relative velocity of B w. Why is my ankle monitor flashing purple. Solution: It is just like previous problems, except they have given a cubic equation instead of a quadratic equation to solve it in the same way. Two cars A and B are running at velocities of 60 km h^. Now, let us tells you about the difference between velocity and speed with respect to 'Average. This implies that besides a rotational motion the wheel experiences a linear motion with a velocity equal to + v cm (see Figure 12. The trajectory of a projectile launched from ground is given by the equation y = -0. b) relative velocity of ground with respect to B. Now, using the formula for relative velocity, V_ {AB} = V_ {A}- V_ {B} = 350 - 500 = 150 m s^ {-1}. Their symptoms may be similar, but they differ largely in how they're transmitted from person to person. Player B wishes to duplicate this bunt, in so far as he also wants to give the ball a velocity parallel to the ground and have his ball travel the same horizontal distance as player A's ball does. Here are the meanings of these four colours. Step 2 : The velocity when it hits the ground is. It runs off the end of the runway! Significance of Understanding Relative Velocity. How to reset service b light on 2007 acura tl. 2(b), and P 1 is the initial system momentum, Figure 1. • v is the velocity of a point on the object with respect to the axis of rotation. B v g, B = v g − v B = 0 - 90$$v g, B = -90 km/h Hence, velocity of ground w. The distance s in feet that the rocket travels from the ground after t seconds is given by $$s(t)=−16t^2+560t$$. Multiply this measurement by the total number of times you walked across the floor. Average velocity: a vector representing the average rate of change of position with respect to time. Answer (1 of 2): I'm not sure what is your question? Is it height in t+3 seconds or just 3 seconds? If it is just t=3 then s(3)=25. At the race that Bolt set the world record, his average ground …. 95ci for the velocity of rocket 2 in the frame of rocket 1. v m,g = v m,A + v Ag = 18 - 54 = -36 km/h Hence, velocity of monkey will be 36 km/h toward north. Two objects (A and B) are moving with velocity V A and V B. A boat is traveling upstream at 11 km/h with respect to the water of a river. this gives a resultant velocity with a forward …. 8 m/s, the velocity has a magnitude of 9. The significance of the negative velocity is that the rate of change of the distance with respect to time (velocity) is negative because the distance is decreasing as the time increases. The height of a projectile can be modeled by s(t) = – 16t^2 + v_0t + s_0, where t is time in seconds, s_0 is the initial height in feet, and v_0 is the initial velocity …. Relative Velocity Solved Examples. Rain is falling vertically with respect to Earth. What is the velocity of the ball when it hit's the ground (Height 0)? calculus. As an object moves upward at a constant speed, its kinetic energy 1) decreases 2) increases 3) remains the same 33. You also know the velocity of the man with . 9 t 2 + 49 t + 15 gives the height in meters of an object after it is thrown vertically upward from a point 15 meters above the ground at a velocity …. With a muzzle velocity of Bulk 9mm Ammo by Speer For Sale at BulkAmmo. 2) The Height of the h (t) = -16t² + 48t + 3. The air is moving at 35 m/s to the north with respect to the ground. Motion in a Straight Line. Find the magnitude and direction of the velocity with which the fuel tank hits the ground if it is from (a) plane A and (b) plane B. The horizontal component of the projectile’s velocity…. Acceleration is a change in velocity, and velocity, in turn, is a measure of the speed and direction of motion. Find an answer to your question When velocity is graphed with respect to time, what does the area under the line represent? A) velocity B) distance C) accelerat… xoyova7791 xoyova7791 12/02/2020 Physics High School answered How long does it take to reach the ground?. Walker, Jearl Fundamentals of physics / Jearl Walker, <NAME>, <NAME>—10th edition. Find the velocity of the rocket 3 seconds after being fired. u = Component of initial velocity …. Using the above expression for relative velocity, one gets. A in a direction opposite to that of A. Solution for (b) Because the initial vertical velocity is zero relative to the ground and vertical motion is independent of horizontal motion, the final vertical velocity for the coin relative to the ground is v y = -5. what is the total time spent by the ball in the. (e) The acceleration vector is the same at the highest point as it is throughout the flight, which is 9. GPE 1 + KE 1 = GPE 2 + KE 2 (KE = 0. Question 2: A car moving with a velocity …. horizontal component of velocity = _____ m sí (2) Page 4 of 24 A The horizontal component of Y's velocity is u. 3 kg and are placed with B along a horizontal frictionless surface. The velocity of the stone can be find , by integrating the acceleration. Vector and Projectile Motion Flashcards. Velocity of A is greater than that of B. Q: If you are walking at constant velocity of 8 km/h and a car passed you by at the speed of 30 km/h from behind, what is the car's velocity from your viewpoint? A: 22 km/h. Reflectivity is a measure of how much precipitation exists in a particular area. Velocity of boat with respect to ground. The acceleration of man with respect to ground is ‘a’. The angle between the velocity of the wind and that of the plane is 90°. 2: Calculate the displacement and velocity at times of (a) 0. Point A moves uniformly with velocity v so that vector v is continually aimed at point B which in its turn moves rectilinearly with velocity u6: Relative Motion in One and Two Dimensions. Electric/Magnetic Velocity Selector A charged particle enters a region with perpendicular electric and magnetic fields. Science Physics University Physics Volume 1 A rock is thrown off a cliff at an angle of 53 ° with respect to the horizontal. As it rises what happens to its vertical component of velocity b. 2 (2/2) You are traveling on an airplane. The object is called a projectile, and its path is called its trajectory. 0 k ^ m / s, and the velocity of reference frame B with respect to C is 2. y = y 0 + v 0 Δt + ½ a (Δt) 2 (relates position and time) 2. All the string are ideal The velocity of C` with respect to ground …. A football player runs the pattern given in the drawing by the three displacement vectors A, B…. Other common names for brain zaps include: brain shivers, electrical shocks, and brain shocks. V AB = the velocity in reference to A and B, V B = the velocity with reference to B. What is the child’s velocity with respect to the ground? a) 5 km/h “upstream” b) 1 km/h “downstream” 2…. Here, we have considered the velocity of the aircraft B as negative because it flies towards the opposite direction to the aircraft A. RELATIVE MOTION ANALYSIS: VELOCITY …. , we will use the relative velocity expression. Using the Pythagorean theorem, the resultant velocity can be calculated as, R 2 = (100 km/hr) 2 + (25 km/hr) 2. Taking Acceleration Due to Gravity G to Be 10 Ms-2 , Find : the Initial Velocity of the …. Which of the following equations can be used to find the magnetic flux as a function of time? A. a constant deceleration of -2 rn/s2. A shot putter releases the shot some distance above the level ground with a velocity of 12. To the pilot flying horizontally at a constant speed relative to the ground the package appears to be falling vertically with a speed vpilot at that same instant. B/A) n = - 2 r B/A, the relative acceleration equation becomes a B = a A + r B/A − 2 r B/A Note that the last term in the relative acceleration equation is not a cross product. So, the relative velocity of train. Relative velocity describes motion with respect to a specific +2. ) What is the angular velocity it is rolling at when it reaches the ground…. A ball is dropped from a height of 80cm after each bounce it rebounds to 70. (b) the velocity Of the Object between t = 40 s and t = 70 s. Therefore, you can see the correct formula is va−vb. a) Relative angular velocity of A wrt C is$\vec{\omega}$only (even direction is same as the original$\vec{\omega}\$). The velocity of the plane with respect to the air is 130 m/s due east. It provides performance similar to self-defense and competition loads for a familiar feel and realistic practice. A block is thrown with a velocity of 2 ms–1 (relative to ground) on a belt, which is moving with velocity 4 ms–1 in opposite direction of the initial velocity of block. b) Velocity is the change of displacement of a body with respect to time. Velocity of a Hot-Air Balloon A hot-air balloon rises vertically from the ground so that its height after t sec is given by the following function. By the formula of relative velocity. A boat is headed with a velocity of 18 meters/second toward the west with respect to the water in a river. 80 meters per second multiplied by 2. g is the acceleration due to gravity (9. Displacement and Velocity are both concepts of motion and an object is said to be in motion if it changes its position with time. The fired bullet will: a) hit the ground first b) hit the ground second 32m 75m; vov=15m/s; 310 a) 3. What would be the magnitude of the boat’s velocity?. We know that when the ball hits the ground y=0 m. Sign convention is taken as south direction as positive. 4 X 10 8m/s c) 3 x 10 8m/s d) 2. What is the velocity of Truck B …. Big Data could be 1) Structured, 2) Unstructured, 3) Semi-structured. Correct answers: 1 question: From a point on the ground a particle is projected with initial velocity u such that its horizontal range is maximum. Average muzzle velocity 920fps. It is also called an independent variable. (b) Earth is moving with velocity -v 1 i with respect to rocket 1. Divide this product by the time period. The velocity of a particle in reference frame A is (2. What are the (a) magnitude and (b) direction of the boat’s velocity with respect to the ground? A child on the boat walks from front to rear at 5. of the relative velocity would have equal the difference between the two . Now the ball is under the influence of gravity, which, on the surface of the Earth, causes all free-falling objects to undergo a vertical acceleration of –9. A projectile is fired with a muzzle velocity of 300 m/s from a gun aimed upward at an angle of 20° with the horizontal, from the top of a building 30m. Calling east the positive direction, you know the velocity of the train with respect to the ground (v TG =60 m/s). Calculate the velocity of the rebound ball with respect to the ground. (b) (i) When two objects move in the same direction (ii) When two objects move in the opposite direction (c) Velocity of the Jet plane V J =500km/hr velocity of gases wrt. v = v 0 + aΔt (relates velocity and time) 3. The velocity of the plane = V a = 100 km/hr The relative velocity of the plane with respect to the ground can be given as The angle between the velocity of the wind and that of the plane is 90°. At time t2 = 57 min, the dog’s displacement from the station is 2. The velocity of the plane = V a = 100 km/hr. This occurs because the acceleration due to gravity is constant at 9. Using Dy=v 1t + 1 2 gt 2 with g=9. 81 m/s² Nov 24, 2015 — A ball is thrown vertically upwards with a speed of 18. RELATIVE MOTION ANALYSIS: ACCELERATION (continued). The velocity of the Earth relative to spaceship 2 is v = 0. At the end of the ground run, the velocity …. C) The velocity components have the same magnitudes at both points, but their directions A tennis ball is thrown from ground level with velocity …. If VA and VB represent the velocities of two bodies A and B respectively at any instant, then, the relative velocity of A with respect to B is represented by VAB Then, VAB = VA - VB —————— (1). A train is moving with a speed of 40 km/h.


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SCIENCE CHINA Information Sciences, Volume 64 , Issue 3 : 130101(2021) https://doi.org/10.1007/s11432-020-3132-4

Learning from group supervision: the impact of supervision deficiency on multi-label learning

• AcceptedJul 30, 2020
• PublishedFeb 7, 2021
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[1] <NAME>, <NAME>. Multi-label learning. In: Encyclopedia of Machine Learning and Data Mining. 875--881. Berlin: Springer, 2016. 1--8. Google Scholar

[2] <NAME>, <NAME>, <NAME>. Matrix Completion for Weakly-Supervised Multi-Label Image Classification. IEEE Trans Pattern Anal Mach Intell, 2015, 37: 121-135 CrossRef Google Scholar

[3] <NAME>, <NAME>, <NAME>. Fast image tagging. In: Proceedings of the 30th International Conference on Machine Learning, 2013. 1274--1282. Google Scholar

[4] <NAME>, <NAME>, <NAME>, et al. Large-scale multi-label text classification on EU legislation. In: Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics, 2019. 6314--6322. Google Scholar

[5] <NAME>, <NAME>, <NAME>, et al. Large-scale multi-label text classification - revisiting neural networks. In: Proceedings of the 25th European Conference on Machine Learning, 2014. 437--452. Google Scholar

[6] iATC-NRAKEL: an efficient multi-label classifier for recognizing anatomical therapeutic chemical classes of drugs. Bioinformatics, 2019, 7 CrossRef Google Scholar

[7] Ontological function annotation of long non-coding RNAs through hierarchical multi-label classification. Bioinformatics, 2018, 34: 1750-1757 CrossRef Google Scholar

[8] <NAME>. A brief introduction to weakly supervised learning. Natl Sci Rev, 2018, 5: 44-53 CrossRef Google Scholar

[9] <NAME>, <NAME>, <NAME>. Speedup matrix completion with side information: application to multi-label learning. In: Proceedings of Advances in Neural Information Processing Systems 26, 2013. 2301--2309. Google Scholar

[10] <NAME>, <NAME>, <NAME>. Multi-label learning with weak label. In: Proceedings of the 24th Conference on Artificial Intelligence, 2010. Google Scholar

[11] <NAME>, <NAME>, <NAME>. Multi-label learning with incomplete class assignments. In: Proceedings of the 24th Conference on Computer Vision and Pattern Recognition, 2011. 2801--2808. Google Scholar

[12] <NAME>, <NAME>. Partial multi-label learning. In: Proceedings of the 32th Conference on Artificial Intelligence, 2018. 4302--4309. Google Scholar

[13] <NAME>, <NAME>, <NAME>, et al. Feature-induced partial multi-label learning. In: Proceedings of the 2018 International Conference on Data Mining, 2018. 1398--1403. Google Scholar

[14] <NAME>, <NAME>. Towards an integrated crowdsourcing definition. J Inf Sci, 2012, 38: 189-200 CrossRef Google Scholar

[15] <NAME>, <NAME>, <NAME>. Multi-Label Learning from Crowds. IEEE Trans Knowl Data Eng, 2019, 31: 1369-1382 CrossRef Google Scholar

[16] <NAME>, <NAME>. Multi-label crowdsourcing learning with incomplete annotations. In: Proceedings of the 15th Pacific Rim International Conference on Artificial Intelligence, 2018. 232--245. Google Scholar

[17] <NAME>, <NAME>. How Do We See Art: An Eye-Tracker Study. Front Hum Neurosci, 2011, 5 CrossRef Google Scholar

[18] Group N N. How people read online: The eyetracking evidence, 2nd edition. Technical report, 2020. Google Scholar

[19] <NAME>, <NAME>. Adam: A method for stochastic optimization. In: Proceedings of the 3rd International Conference on Learning Representations, 2015. Google Scholar

[20] <NAME>, <NAME>, <NAME>, et al. Dropout: a simple way to prevent neural networks from overfitting. J. Mach. Learn. Res., 2014, 15(1): 1929--1958. Google Scholar

[21] <NAME>, <NAME>, <NAME>. Learning multi-label scene classification. Pattern Recognition, 2004, 37: 1757-1771 CrossRef Google Scholar

[22] <NAME> and <NAME>. Random k -labelsets: An ensemble method for multilabel classification. In: Proceedings of the 18th European Conference on Machine Learning, 2007. 406--417. Google Scholar

[23] <NAME>, <NAME>, <NAME>, et al. Classifier chains for multi-label classification. In: Proceedings of the 20th European Conference on Machine Learning, 2009. 254--269. Google Scholar

[24] <NAME>, <NAME>. A kernel method for multi-labelled classification. In: Proceedings of Advances in Neural Information Processing Systems 14, 2001. 681--687. Google Scholar

[25] <NAME>, <NAME>, <NAME>, et al. Sparse local embeddings for extreme multi-label classification. In: Proceedings of Advances in Neural Information Processing Systems 28, 2015. 730--738. Google Scholar

[26] <NAME>, <NAME>. A Review on Multi-Label Learning Algorithms. IEEE Trans Knowl Data Eng, 2014, 26: 1819-1837 CrossRef Google Scholar

[27] <NAME>, <NAME>, <NAME>, et al. Multi-label prediction via compressed sensing. In: Proceedings of Advances in Neural Information Processing Systems 22, 2009. 772--780. Google Scholar

[28] <NAME>, <NAME>. Multilabel Classification with Principal Label Space Transformation. Neural Computation, 2012, 24: 2508-2542 CrossRef Google Scholar

[29] <NAME>, <NAME>. Efficient multi-label classification with many labels. In: Proceedings of the 30th International Conference on Machine Learning, 2013. 405--413. Google Scholar

[30] <NAME>, <NAME>. Multilabel classification with group testing and codes. In: Proceedings of the 34th International Conference on Machine Learning, 2017. 3492--3501. Google Scholar

[31] <NAME>, <NAME>, <NAME>, et al. Transduction with matrix completion: Three birds with one stone. In: Proceedings of Advances in Neural Information Processing Systems 23, 2010. 757--765. Google Scholar

[32] <NAME>, <NAME>. Multilabel classification with label correlations and missing labels. In: Proceedings of the 28th Conference on Artificial Intelligence, 2014. 1680--1686. Google Scholar

[33] <NAME>, <NAME>, <NAME>, et al. Learning low-rank label correlations for multi-label classification with missing labels. In: Proceedings of the 2014 International Conference on Data Mining, 2014. 1067--1072. Google Scholar

[34] <NAME>, <NAME>, <NAME>, et al. Semi-supervised low-rank mapping learning for multi-label classification. In: Proceedings of the 28th Conference on Computer Vision and Pattern Recognition, 2015. 1483--1491. Google Scholar

[35] <NAME>, <NAME>, <NAME>. ML-MG: multi-label learning with missing labels using a mixed graph. In: Proceedings of the 2015 International Conference on Computer Vision, 2015. 4157--4165. Google Scholar

[36] <NAME>, <NAME>. Multi-label classification with error-correcting codes. In: Proceedings of Hsu C and <NAME>, editors, Proceedings of the 3rd Asian Conference on Machine Learning, 2011. 281--295. Google Scholar

[37] <NAME>, <NAME>, <NAME>, et al. Progressive identification of true labels for partial-label learning. 2020,. arXiv Google Scholar

[38] <NAME>. On-line learning and stochastic approximations. In: Proceedings of Online Learning in Neural Networks. Cambridge University Press, 1998. 9--42. Google Scholar

[39] <NAME>, <NAME>. Scalable training of L1-regularized log-linear models. In: Proceedings of the 24th International Conference on Machine Learning, 2007. 33--40. Google Scholar

[40] <NAME> and <NAME>. Learnability of the superset label learning problem. In: Proceedings of the 31th International Conference on Machine Learning, 2014. 1629--1637. Google Scholar

[41] <NAME> , <NAME> . Multilabel Neural Networks with Applications to Functional Genomics and Text Categorization. IEEE Trans Knowl Data Eng, 2006, 18: 1338-1351 CrossRef Google Scholar

• Figure 1

(Color online) Different types of supervision information for multi-labeled data.

• Figure 2

(Color online) Test results show how the number of positive groups impacts learning. $x$-axis is the epoch, and $y$-axis is the MSE. The shadow area shows the standard deviation (STD) of ten random trials under the same setting. iris the number of irrelevant labels in each positive group, and rcshows the relevant label coverage. The number of relevant label per group is fixed to be $1$, and the irrelevant label coverage is fixed to be $0.5$. (a) ir: 2, rc: 0.25; (b) ir: 2, rc: 0.5; (c) ir: 2, rc: 0.75; (d) ir: 2, rc: 1.0; (e) ir: 4, rc: 0.25; (f) ir: 4, rc: 0.5; (g) ir: 4, rc: 0.75; (h) ir: 4, rc: 1.0.

• Figure 3

(Color online) Test results show how the relevant label coverage (rc) impacts learning. $x$-axis is the epoch, and $y$-axis is the MSE. Under the same setting, the shadow area shows the variance of ten random trials. iris the number of irrelevant labels in each positive group, and icshows the irrelevant label coverage. The number of relevant label per group is fixed to be $1$, and the number of positive groups is fixed to be $3$. (a) ir: 1, ic: 0.25; (b) ir: 1, ic: 0.5; (c) ir: 1, ic: 0.75; (d) ir: 1, ic: 1.0; (e) ir: 2, ic: 0.25; (f) ir: 2, ic: 0.5; (g) ir: 2, ic: 0.75; (h) ir: 2, ic: 1.0.

• Figure 4

(Color online) Test results show how the irrelevant label coverage (ic) impacts learning. $x$-axis is the epoch, and $y$-axis is the MSE. Under the same setting, the shadow area shows the STD of ten random trials. ngis the number of positive groups, and rcshows the relevant label coverage. The number of relevant label per group is fixed to be $1$, and the number of irrelevant label per group is fixed to be $2$. (a) ng: 2, rc: 0.25; (b) ng: 2, rc: 0.5; (c) ng: 2, rc: 0.75; (d) ng: 2, rc: 1.0; (e) ng: 3, rc: 0.25; protectłinebreak (f) ng: 3, rc: 0.5; (g) ng: 3, rc: 0.75; (h) ng: 3, rc: 1.0.

• Figure 5

(Color online) Test results show how the number of relevant labels per positive group impacts learning. $x$-axis is the epoch, and $y$-axis is the MSE. Under the same settings, the shadow area shows the STD of ten random trials. iris the number of irrelevant labels per positive group, and icshows the irrelevant label coverage. The number of positive groups and the relevant label coverage are fixed to be $3$ and $0.5$ respectively. (a) ir: 1, ic: 0.25; (b) ir: 1, ic: 0.5; (c) ir: 1, ic: 0.75; (d) ir: 1, ic: 1.0; (e) ir: 2, ic: 0.25; (f) ir: 2, ic: 0.5; (g) ir: 2, ic: 0.75; (h) ir: 2, ic: 1.0.

• Figure 6

(Color online) Test results show how the number of irrelevant labels per positive group impacts learning. $x$-axis is the epoch, and $y$-axis is the MSE. Under the same setting, the shadow area shows the STD of ten random trials. ngis the number of positive groups, and icshows the irrelevant label coverage. The number of relevant labels per group and the relevant label coverage are fixed to be $1$ and $0.5$, respectively. (a) ng: 2, ic: 0.25; (b) ng: 2, ic: 0.5; (c) ng: 2, ic: 0.75; (d) ng: 2, ic: 1.0; (e) ng: 3, ic: 0.25; (f) ng: 3, ic: 0.5; (g) ng: 3, ic: 0.75; (h) ng: 3, ic: 1.0.

•

Algorithm 1 GS-MLL: group-supervised multi-label learning

Require:the training set $\cD~=~\{(\x_1,~\S_1),~\ldots,~(\x_n,~\S_n)\}$; epoch number $T$; number of mini batches $B$;

Output:$\Theta$, the model parameter for $\g(\x;\Theta)$;

Let $\cA$ be any stochastic optimization algorithm;

$t=1$;

while $t\le~T$ do

$t~=~t+1$;

Shuffle $\cD$ into $B$ mini-batches;

$b~=~1$;

while $b\le~B$ do

Pick the $b$th mini batch;

Compute the empirical risk $L$ on the mini batch by (9);

Calculate the gradient $-\nabla_\Theta~L$;

Update $\Theta$ by $\cA$;

$b~=~b+1$;

end while

end while

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text:
Opened 7 years ago

Closed 6 years ago

# Loading of Test Manager takes too long and sometimes time out

Reported by: Owned by: nicualex@… <NAME> normal TestManagerForTracPlugin major solarwind 0.12

### Description

first of all , your plugin is very useful and much appreciated. we do have an issue though.

we've installed 1.4.4 and we've started to add existing test cases (from a previous system). we have about 3000 now. when trying to access the Test Manager tab , it is painfully slow to load ... most of the time, the browser is timing out. Once we're in , navigating the test catalogues and cases is alright.

I should say that the rest of our Trac is working perfectly.

I was wondering if you've seen this before and have any hints for us on how to fix it.

cheers, alex

### comment:1 Changed 7 years ago by <NAME>

Hi Alex, I haven't been reported performance issues so far, you are the first.

So the problem seems related to only the base catalogs list. Once browsing a single catalog, everything is ok, right?

What about showing only the top catalog names in the first page? Would this be acceptable?

By the way, in 1.4.5 I've added a test case importing feature you may want to look at.

Let me know. Ciao, Roberto

### comment:2 Changed 7 years ago by anonymous

i'm not entirely sure i understand your suggestion (about the top catalog names in the first page). i've attached a snapshot of our main page , for better understanding. I've also added my colleague Kelvin in the loop. He's in a much better position to comment on this topic. I believe he just installed the new version , i haven't had the chance to try it yet.

cheers, Alex

### comment:3 Changed 7 years ago by solarwind

Summary: singapore → Loading of Test Manager takes too long and sometimes time out

### comment:4 Changed 7 years ago by solarwind

Hi Roberto,

I believe we are already only displaying the top catalog names as Alex mentioned(as shown in the attachment) Some additional info - I am using apache server, with MySQL backend. I am using trac.fcgi. When I access test manager catalog, I see trac.fcgi taking up 100% of CPU usage on my machine.

However I have no problems accessing ticket reports during which trac.fcgi takes up less than 2% of CPU usage

Not sure what is causing the discrepancy in performance? Any ideas or solutions would be welcome.

Thanks, Kelvin

### comment:5 follow-ups:  6  7 Changed 7 years ago by <NAME>

Hi Kelvin, the suggestion about showing only the catalog names in the root page was actually kind of a proposal on how to change the plugin's code to run faster :D

Currently the catalogs are yes collapsed, but anyway their contents have already been loaded in the browser. There is no optimization in here.

I see two alternatives:

1. Less effort required: show only the catalog names in the root page, not expandable. You must click on the catalog itself to navigate to its page ans see its contents. This behavior may be activated by an option in the trac.ini file.
2. With more effort I may add the logic to load each top-level catalog's contents only when someone clicks on it.

I think I may do number 1 pretty quickly. Do you think it may be OK?

Ciao, Roberto

### comment:6 in reply to:  5 Changed 7 years ago by solarwind

Hi Robert,

Yes, that is good enough for me, I can check the new version to see if the performance is improved

Thanks! Kelvin

### Changed 7 years ago by anonymous

mysql log of test manager database access

### comment:7 in reply to:  5 Changed 7 years ago by solarwind

Some extra info for you:

A root catalog by itself can already consist of a few thousand test cases, and it contains subcatalogs which may contain hundreds of test cases. It would help if the sub-catalogs are taken care of as well (i.e. only load the subcatalog contents when clicked)

Also I found from mysql log that the database access is done one wikipage at a time, refer to mysql.log.110622, and in each second there are anywhere between 20 to 30 queries to mysql, so if I have a few thousand test cases, it would take a few minutes for the test catalog to load. And if there are a few concurrent users, you can imagine that many users will experience the webpage timing out.

It seems that you are using the trac API WikiPage to access the database to generate your html, which can only be done one test case at a time. Any chance you can somehow query the data you need at one go using trac.db API instead?

Am not sure if it would work though, just thinking aloud

Thanks again, Kelvin

### comment:8 Changed 7 years ago by <NAME>

Hi Kelvin, thanks for your problem analysis, I couldn't find the time to face this ticket yet (I focused on smaller/easier tickets instead :D).

You're right, I currently use th Wiki API to query catalogs and test cases, and I had no idea it was so poorly optimized!

I will try and use the db API directly, and see how it goes.

<NAME>

### comment:9 Changed 7 years ago by <NAME>

Hi Kelvin, I have found a very simple way of fixing this, using the db api as you suggested.

You can fiund in attachment the modified macros.py file, to be replaced into the "testman4trac/trunk/testmanager/" directory.

Build the whole plugin and replace the "TestManager-1.4.6-py*.egg" file into your Trac server's "plugin" directory.

Please, let me know if this speeds up things or not.

<NAME>

### comment:10 Changed 7 years ago by <NAME>

Status: new → assigned

<NAME>

Last edited 4 years ago by <NAME> (previous) (diff)

### comment:11 Changed 7 years ago by solarwind

Hi Robert,

That's fast! I have tried your changes, the webpage load speed has definitely improved. MySQL database access has been much reduced also. There is a bug though... The top level catalog names are wrong. However, when I click on a top level catalog name to go to its wiki page, the catalog name there is correct

The subcatalog names are fine though, just the top level ones are wrong

Thanks again and cheers, Kelvin

### comment:12 follow-up:  13 Changed 7 years ago by <NAME>

Hi Kelvin, I'm glad it works :D

Actually I can't reproduce your problem with the top catalog names... I've tried with Chrome, IE7 and Firefox 3.6, so I guess it's not a browser-related problem.

Could you attach a couple of screenshots, one of the top-level list and one of a top-level catalog once opened?

I suspect it may have something to do with the catalog names.

<NAME>

### Changed 7 years ago by solarwind

top level category

### comment:13 in reply to:  12 ; follow-up:  14 Changed 7 years ago by anonymous

Hi Roberto,

Thanks for the quick response. I have attached the Images

First when I access the top level TopLevelCat.png is shown. The category names are displayed wrongly. When I click on the category "Level 3 G1", ClickedOnLevel3G1.png is shown. Then when I click on "HDMI, FULL HD, CEC", ClickedOnHdmiFullHdCec.png is shown. Finally when I click on "HDMI CEC", I get this ClickedOnHdmiCec.png

Regards, Kelvin

### comment:14 in reply to:  13 ; follow-up:  15 Changed 7 years ago by solarwind

Hi Roberto,

Just a thought, my colleague commented the test cases seems to be from some time back and did not incorporate the latest changes, perhaps the test cases used to generate the tree etc are not using the latest test case revisions?

Cheers, Kelvin

### comment:15 in reply to:  14 Changed 7 years ago by solarwind

Hi Roberto,

In the macro.py, I notice that the line

sql = "SELECT name, text FROM wiki WHERE name LIKE '%s%%' AND version=1 ORDER BY name" % curpage

may be causing the problem by only selecting version 1 wikipages?

Cheers, Kelvin

### comment:16 follow-up:  17 Changed 7 years ago by <NAME>

Hi Kelvin, I can't teach you anything, you're too smart :D

You're right, I did that to only get one wiki page verison, completely forgetting that the version is there to do something :D

Please find in attachment the updated macro.py file, with a fixed query, and let me know how it goes.

Ciao, Roberto

### comment:17 in reply to:  16 Changed 7 years ago by solarwind

Hi Robert,

Unfortunately I got this error:

Oops…
Trac detected an internal error: NotSupportedError: (1235, "This version of
MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'")
This is probably a local installation issue.

I was running mysql 5.1, which I have upgraded to 5.5 but still face the same issue

I then tried what I think would be similar to what you are trying to do (I think) by changing the following

    for subpage_name, text in _list_matching_subpages(env, curpage+'_'):
subpage_title = get_page_title(text)

to...

    prev_page_title_result = ''

for subpage_name, text in _list_matching_subpages(env, curpage+'_'):
subpage_title = get_page_title(text)
# only get latest revision of wiki page
if(prev_page_title_result==subpage_title):
continue;
prev_page_title_result = subpage_title

In this case. Only the top level catalog is ok, but the subcatalogs are still incorrect

Cheers, Kelvin

### comment:18 Changed 7 years ago by <NAME>

Wow! SQLite supports it and MySQL doesn't... O_o

Your code may work, but still requires the python code to go through all of the records...

Let me try and find a solution that delegates the work to the database.

I'll let you know.

<NAME>

### comment:19 follow-up:  20 Changed 7 years ago by <NAME>

Yet another fixed query.

I could only try it on SQLite, but according to here, this porkaround :D should work on MySQL.

Please, let me know if they're right.

<NAME>

### comment:20 in reply to:  19 ; follow-up:  21 Changed 7 years ago by solarwind

Hi Roberto,

I actually came across the post also and tried it on Friday but it didn't work. Maybe my query was wrong. I'll try with your macros.py on Monday and let you know.

Thanks again, Kelvin

### comment:21 in reply to:  20 Changed 7 years ago by solarwind

Hi Roberto,

I got this error with the new macros.py

Oops… Trac detected an internal error: OperationalError: (1054, "Unknown column 'w.name' in 'where clause'") This is probably a local installation issue.

Any ideas?

Cheers, Kelvin

### comment:22 follow-up:  23 Changed 7 years ago by <NAME>

Hi Kelvin, I'm now getting the same error... not sure what happened since I made it work...

Anyway, I changed the approach and found a better and simpler way of doing the query, which works fine in my env.

Please find in attachment the new macros.py and let me know :D

<NAME>

### Changed 7 years ago by <NAME>

New approach using group by

### comment:23 in reply to:  22 ; follow-up:  24 Changed 7 years ago by solarwind

Hi Roberto,

There is syntax error, but the generated tree is still incorrect. I tried with your most recent macros.py, as well as using the new query with your previous macros.py (I noticed there were many changes in your previous macros.py which was not reflected in this most recent one)

Both results are same as my comment 13, the wikipage versions used seem to be wrong

Cheers, Kelvin

### comment:24 in reply to:  23 ; follow-up:  25 Changed 7 years ago by solarwind

Sorry, I meant there is NO syntax error, but wikipage versions used for the tree are still incorrect

### comment:25 in reply to:  24 Changed 7 years ago by anonymous

The query results seems ok though, so probably it is somewhere else

Cheers, Kelvin

### comment:26 Changed 7 years ago by <NAME>

Kelvin, the fix works in my env...

Could you please double check the catalog titles?

The problem with the catalog titles was partly caused by the version and partly by the trailing clause "ORDER BY name", which MUST be there for the algorithm to work correctly.

Please le me know. <NAME>

### comment:27 Changed 6 years ago by <NAME>

Resolution: → fixed assigned → closed

Fixed in 1.4.7, with a better query that works on any supported database.

I encourage you to try it out and let me know how it works for you.

<NAME>

### comment:28 Changed 6 years ago by solarwind

Hi Roberto,

Sorry for the late reply, was busy with other stuff. I have tried your latest release 1.4.7 and it finally works now! Previous versioning problems are ok now. I'll check with previous test source code to see what was the difference

Thank you very much, you've been most helpful!

Cheers, Kelvin

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