Question

Two identical balls A and B collide head on elastically. If velocities of A and B, before the collision are +0.5 m/s and -0.3 m/s respectively, then their velocities, after the collision, are respectively

• A. -0.5 m/s and +0.3 m/s
• B. +0.5 m/s and +0.3 m/s
• C. +0.3 m/s and -0.5 m/s
• D. -0.3 m/s and +0.5 m/s

Answer 1

The correct option is C +0.3 m/s and -0.5 m/s

When identical balls collide $elastically$ they just $exchange$ their $SPEEDS$ and get reversed.

This can be verified by applying the $momentum$ conservation and $energy$ conservation, yes energy remains

conserved for elastic collisions.

so the exchanged velocities will be following $v_1=0.3m/s$ and $v_2=-0.5m/s$