Two balls of different masses collide head on . After the collision, the ball sremain at rest, and no external force act on them. Which statements is true about the speed of the balls before at the collision ?

Options

A. They must have been different velocity, and the collision was inelastic.
B. they must have been different, and the collision was elastic.
C. they must have been identical, and the collision was inelastic
D. No combination of speed values could have caused both balls to stop after the collision.

Answer

A

Explanation

`m_(1)u_(1)-m_(2)u_(2)=0`
`0=0/(u_(1)-u_(2))`