If they told you a body is at equilibrium, or if it's uniform, or if it's non-uniform. What do you get from these informations? I'm talking about moments here.

Question

paki · Answer

if a body is in equilibrium then vector sum of all forces on it is equal to null... if the body is in static equilibrium then the net torque on the body is also zero... there may be more than one force as well a torque acting on the body... For example... if you're sitting down, the force of gravity is acting on you, but the normal force of the seat you're on equals the magnitude of that force and it opposite in direction-you're in equilibrium, but there are still forces acting on you...

kainui · Answer

If something is at equilibrium that means everything that's acting on that thing are all cancelling each other out. So in the context of forces in equilibrium, the force of gravity acting on a chair is the same as the force exerted by the chair to hold itself up by its legs.

If an object is uniform, this could mean several things but for the most part it just means there's a constant distribution of something in that object. For instance if an object's mass is uniformly distributed then that just means it has a constant density since no parts are denser than other parts. Something that's non-uniform is really just the opposite of this, it might have a density described by a function, maybe not.

A good example of something that has a uniform distribution of mass would be something like a plastic spoon or maybe paperback book -- they're each just solid plastic or paper and consistent in their content. Your arm is definitely not a uniform distribution of mass. Your skin and the blood in your arm is a lot less dense than the material your bone is made out of.

aroub · Answer

This was really helpful. Thanks :)