A student throws a ball with a speed v=15m/s at the rear of the receding truck traveling 7m/s. If the collision is elastic and perpendicular to the surface of the truck , what will be the rebound velocity of the ball?
answer is 1m/s but i don't know how to calculate it

Question

A student throws a ball with a speed v=15m/s at the rear of the receding truck traveling 7m/s. If the collision is elastic and perpendicular to the surface of the truck , what will be the rebound velocity of the ball?
answer is 1m/s  but i don't know how to calculate it

anonymous · Answer

@Michele_Laino help please

michele_laino · Answer

hint:
since the collision is elastic, then the total kinetic energy is conserved, and the total momentum is also conserved

anonymous · Answer

what would be the formula we will use?