What are all the forces acting on the cart and hanging mass?

Question

A cart m1=400g rolls along a track with very low friction. It is attached by a string over a pulley to an object M2=40g that is hanging vertically. Both are at rest when m2 is released.

what are all the forces acting on the cart. What are all the forces acting on the hanging mass?

Answer 1

On the hanging mass - force of gravity = m*g = 0.04*10 = 0.4N. This is balanced by the tension in the string from which it hangs = 0.4 N
These two forces keep the hanging mass in place.
On the cart, there is tension in the string = 0.4N,
then there is the frictional force = 0.4N holding it back. Of course the force due to gravity acts on the cart = 0.4 * 10 = 4N. This is balanced by the normal reaction.