# ja72

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bio website location United States age member for 3 years, 9 months seen 4 hours ago profile views 901

Started programming on a ZX spectrum in the 80's and have moved through Assembly, Turbo Pascal, C++, C#, Fortran. My main area of focus is engineering and scientific computing like numerical methods and 3D graphics.

# 2,159 Actions

 Aug20 revised related to projectile motion Some formatting for readability Aug20 comment Which way does the scale tip? Buoyancy acts upwards on the spheres (purple arrows) and its reaction acts downwards on the beakers. Aug18 revised Massive ropes and tension added 141 characters in body Aug18 answered Massive ropes and tension Aug18 comment Massive ropes and tension Is $m g$ the total weight of the rope, or an additional hanging weight on the lowest point? Aug15 comment Do objects rotate around the torque vector or its center? Note that if a pure torque is applied on a connected body (part of chain of bodies connected with joints) then it will rotate about the effective center of mass. That is the point where if a force is applied the connected body will purely translate. Aug15 comment Which way does the scale tip? Actually there would be buoyancy on the rod, and it's reaction would contribute to the right side being pushed down. Aug14 comment Reduced mass and harmonic mean Harmonic mean is like adding resistors in parallel. Effectively you are adding conductance $1/R$ terms. With reduced mass you are adding mobility $1/m$ terms. Aug14 comment Calculating torque in 3D? Did you know that if only pure torques are applied on a rigid body (such that sum of forces is zero) then the body would rotate about it's center of mass. To rotate a body about an axis away from the COM you have to apply a net force. Aug14 awarded Good Answer Aug14 comment Which way does the scale tip? @pnizzle the weight of the steel ball is mostly supported by the cord. Only partial steel weight (reaction to buoyancy) is felt by the beaker on the right. In the end, you want to compare forces. Aug13 reviewed Approve suggested edit on Which way does the scale tip? Aug13 comment Put a bullet into orbit around the moon Just put a M1 Abrams on the moon. Problem solved. Aug13 comment Put a bullet into orbit around the moon Unfortunately you need oxygen to set off a gun. Aug13 comment Grain boundary sliding in creep Maybe the grain boundaries have to lie perpendicular to the shear plane direction. Maybe anisotropic properties help in creep if the grain direction can be controlled. Aug13 comment Which way does the scale tip? @Trengot then you have $B_1=0$. That does not change the problem. Aug13 awarded Nice Answer Aug12 answered torque on a body without any supporting point Aug12 comment torque on a body without any supporting point The question has been answered here Why is moment dependent on the distance from the point of rotation to the force also. Aug12 comment torque on a body without any supporting point possible duplicate of Force applied off center on an object
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