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## for General Physics 1

o Note that 0.5 may be given as partial point for all these EC tasks.
o Submission of an EC task does not automatically translate to an EC point.
o Any part of the task that is plagiarized or copied automatically voids the EC task.
o Apart from the Christmas Mobile EC task, the rest must be done individually.

## I. For those who prefer problem solving and deriving

1. The movement of an ideal roller coaster relies on the initial gravitational potential energy at the
release point, the highest position of the roller coaster where the initial velocity is zero.

release point
top of loop-the-loop

Assume that the roller coaster is in UCM as it goes around the loop-the-loop of radius r. For it to
negotiate the loop, its acceleration at while at the top of the loop must be at least the acceleration
due to gravity g = 9.8 m/s2. For this problem, you will apply UCM and LoCE.
o Derive an equation for the minimum release height h of a roller coaster to successfully
negotiate a loop-the-loop of radius r, that is, a formula where h is a function of r. Write the
derivation on a size 1. State all assumptions and define all variables. (2 points)
o Using the roller coaster setup in our Physics laboratory, you may relate the height of release
h and the radius of the loop-the-loop by trial and error. Take pictures of your ‘experiment’
and provide measurements of h and r to justify the equation that you can use to describe
the measurements. Write the data, equation and place pictures on a size 1. (1 point)

2. In Physics, there are grand theories that apply to simple and complex situations alike. Take NULG
for example. When an object is near the surface of a planet, in this case the Earth, its potential
energy due to gravity is equal to:

U = mgh (1)

If the object is placed at a considerable distance from the center of the Earth, its gravitational
potential energy becomes:

𝐺𝑀𝑚
𝑈 = − (2)
𝑟

## Equation (2) simplifies to equation (1) given the following assumptions/conditions:

• M is the mass of the Earth
• r = rE + h, where r is the distance of the object from the center of the Earth as the sum of
the radius of the Earth rE and its distance from the surface h
• h ≪ rE, which means that the distance of the object from the surface h is very much less (≪)
than the radius of the planet rE
𝑎
• 1 + ≈ 1 if a ≪ b (The fraction results to a very small number that is insignificant when
𝑏
added to 1. For practical purposes, the expression is simply equal to 1.)

Show that:
𝐺𝑀𝑚 𝐺𝑀𝑚
𝑈= −
𝑟 𝑟𝐸 + ℎ

## reduces to U = mgh using the conditions set above. (2 points)

3. You made a prototype weather/climate monitoring device for your General Chemistry 1 class. What
is the minimum price that you will pay if the satellite must:
• weigh as it is measured using a weighing scale in the lab
• be launched from Manila
• must be geostationary

Carefully study the implications of those three conditions. Print your solution on an 8.5” x 11” paper,
following the format of Performance Task 1.4, Cost of Sending a Satellite to Space. (2 points)

4. Consider a roller coaster with a total mass of 1000 kg. It was released from a height of 500 m on an
inclined, frictionless ramp. After some time, it reaches the flat part of tracks where there is friction.
It eventually comes to a stop.

release point

vf = 0
part with friction

Given these conditions, how far on the flat tracks will the roller coaster go? Hint: Use LoCE, FBD,
NFE and kinematic equations. Use a coefficient of kinetic friction for steel on steel equal to 0.6. The
following are the kinematic equations that might be helpful to you:

where vf is the final velocity, vi is the initial velocity, a is the acceleration, d is the distance travelled,
and a is acceleration. (3 points)

## II. For those who prefer explaining

5. Write a position paper based on the premise: THBT the Philippines will benefit from a national space
program. Just like in a debate, provide convincing pieces of evidence.

## Touch on the topics of:

o considerations in building and launching satellite/rocket
o life of a satellite (from conception to decommission)
o astrophysics environment in the Philippines

## The essay must not be less than 20 – 30 sentences long. (2 points)

6. Most sci-fi movies show habitable spaceships that rotate with respect to their own axis. This is to
supposedly provide an upward force (directed to the axis of rotation) on the inhabitants of the ship
equivalent to what is experienced on Earth. On a size 1:
o Prove that designing the ship does not depend on the mass of each inhabitant to provide
the suitable upward force. (1 point)
o State two factors or variables that affect the design of the spaceship in terms of providing
the upward force. (1 point)

7. Physics of Carnival Rides. Describe the motion of three rides in Enchanted Kingdom.
o EKstreme: http://enchantedkingdom.ph/posts/ekstreme-tower/
o Anchor’s Away: http://enchantedkingdom.ph/posts/anchors-away/
o Flying Fiesta: http://enchantedkingdom.ph/posts/flying-fiesta/
o Wheel of Fate: http://enchantedkingdom.ph/posts/wheel-of-fate/
o Grand Carousel: http://enchantedkingdom.ph/posts/grand-carousel/

a) Draw the FBD of the rider at the beginning, during and at the end of the ride.
b) Determine NFEs and consider different situations that the ride offers (i.e. seat placement,
ride orientation). Include those situations that involve increased G-forces, “weightlessness”
and accelerations.
c) write-up for each ride should be exactly 10 sentences long
d) write everything on a size 1
e) one EC point per ride

## IV. For those who prefer visiting science areas of interest

Visit any of the following science areas of interest with a responsible adult as a companion. Then, submit
a travel journal which contains the following. The travel journal must be printed on an 8.5” x 11” paper.
o entrance tickets
o picture of you with the responsible adult while inside the museum
o an essay on a museum exhibit that you find interesting (20 – 30 sentences)
o an essay on how any of our topics in General Physics 1 relate to another museum exhibit
which is not the topic on item (c). The relationship of the physics concept to the exhibit
must be obvious, or in Filipino, not “pilit.” The essay must not be less than 20 sentences
and not more than 30 sentences.

The following are the only science areas of interest that you can visit, each for 2 EC points.
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