If two billiard balls collide, what happens to the systems overall momentum ?

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

Aria drove to the store, did some shopping, and then came home. during maria's trip, when was her displacement equal to zero?