I don't understand at all

Debbie places two shopping carts in a cart corral she pushes the first cart which then pushes a second cart what force is being exerted

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)