This is a classic introductory physics problem. Basically, you have a cart on a frictionless track (call this m 1) with a string that runs over a pulley to another mass hanging below (call this m ...

Nonetheless, I digress. Since you already have a picture of the atwoods machine, I will draw two free body (force) diagrams. ... No. These are not the only forces on the pulley.

Pulley systems ease lifting with ropes over wheels. Single pulleys change force direction; fixed pulleys change direction; movable pulleys reduce effort. Adding pulleys creates mechanical advantage.