Question

A 1500 kg car moving at 25 m/s hits a stationary car of the same mass. They stick together and move at 12.5 m/s. Compare the total kinetic energy before and after the collision to see if it was conserved.

(1 point)
Responses

Kinetic energy was created during the collision.
Kinetic energy was created during the collision.

Kinetic energy was not conserved; it increased.
Kinetic energy was not conserved; it increased.

Kinetic energy was conserved; it stayed the same.
Kinetic energy was conserved; it stayed the same.

Kinetic energy was not conserved; it decreased.
Kinetic energy was not conserved; it decreased.

Answer 1

Initial KE = 1/2(1500)(25^2) = 468,750 J.
Final KE = 1/2(3000)(12.5^2) = 234,375 J.

The kinetic energy decreased (final is half the initial). So: "Kinetic energy was not conserved; it decreased."