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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.


Aug
20
revised related to projectile motion
Some formatting for readability
Aug
20
comment Which way does the scale tip?
Buoyancy acts upwards on the spheres (purple arrows) and its reaction acts downwards on the beakers.
Aug
18
revised Massive ropes and tension
added 141 characters in body
Aug
18
answered Massive ropes and tension
Aug
18
comment Massive ropes and tension
Is $m g$ the total weight of the rope, or an additional hanging weight on the lowest point?
Aug
15
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.
Aug
15
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.
Aug
14
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.
Aug
14
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.
Aug
14
awarded  Good Answer
Aug
14
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.
Aug
13
reviewed Approve suggested edit on Which way does the scale tip?
Aug
13
comment Put a bullet into orbit around the moon
Just put a M1 Abrams on the moon. Problem solved.
Aug
13
comment Put a bullet into orbit around the moon
Unfortunately you need oxygen to set off a gun.
Aug
13
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.
Aug
13
comment Which way does the scale tip?
@Trengot then you have $B_1=0$. That does not change the problem.
Aug
13
awarded  Nice Answer
Aug
12
answered torque on a body without any supporting point
Aug
12
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.
Aug
12
comment torque on a body without any supporting point
possible duplicate of Force applied off center on an object