A student with a mass of 40 kg can throw a 15-kg ball with a relative speed of 5.0 m/s.The student is standing at rest on a cart with a mass of 12 kg that can move over the ground without friction.If the student throws the ball horizontally,what is the student's speed relative to the ground?
A)1.4 m/s
B)5.0 m/s
C)3.9 m/s
D)1.9 m/s
E)1.1 m/s

Question

Quizplus · Accepted Answer

Using conservation of momentum, the total momentum before and after the throw must be equal. Initially, the momentum is zero. After the throw, the momentum of the ball and the student-cart system must cancel each other out. Solving for the student's speed relative to the ground gives 1.1 m/s.

A Student with a Mass of 40 Kg Can Throw