why is the ball bounce on wall come to again
Answers
Newton’s third law.
When the ball hits the wall, it’s got energy. That energy has got to go somewhere. Some of it goes to heat and sound. The ball has a lot of elasticity and the wall doesn’t (or it shouldn’t anyway) and the ball deforms and squishes in on itself. The ball now wants to get back to shape, especially if it’s pressurised like a blown-up football. So it does, and in getting back into shape it releases the energy stored up in the deformation, which pushes against the wall, and since the wall still can’t move anywhere what happens is it pushes off the wall and back where it came turning the stored energy into kinetic. It’s still the same energy that came from your hand (minus a bit in losses) but it got converted into kinetic, elastic and back to kinetic again.
There is an equal and opposite force on the ball in the upward direction (Newton's Third Law), which makes it bounce. The conversion of elastic energy to kinetic makes it rise against the ground. If the same rubber ball is bounced off a carpet, it won't rise or bounce to the same height as when bounced on solid ground.