A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system
A) is one quarter as much as before.
B) is the same as before.
C) is one third as much as before.
D) is one fourth as much as before.
E) is half as much as before.

Question

Quizplus · Accepted Answer

In a perfectly inelastic collision, where two objects stick together, the kinetic energy is not conserved. The final kinetic energy is half of the initial kinetic energy when two identical masses collide and stick together.

A Railroad Car Collides with and Sticks to an Identical