A ball moving with a velocity v hits a massive wall moving towards the ball with a velcocity u. An elastic impact lasts for a time Delta t.

A ball moving with a velocity v hits a massive wall moving towards the

1.	A ball moving with a velocity v hits a massive wall moving towards the ball with a velcocity u. An elastic impact lasts for a time Delta t.
Answer» The average elastic FORCE acting on the ball `(m(U+v))/(Delta t)` The average elastic force acting on the ball is `(2m(u+v))/(Delta t)` The KINETIC ENERGY of the ball increases by `2m u(u+v)` The kinetic energy of the ball remains the same after the collision Answer :B::C