Question

Question 6.Why does a ball dropped from a certain height not bounce back 1 point

to the same height it was dropped from? *

Answer 1

Because the coefficient of restitution is less than 1.

This coefficient is 1 for a perfectly elastic collision.

Some of the energy of the fall is absorbed by the ball so the ball cannot return to its original height.

Also, you have the effects of air resistance and some energy absorption of the the reflecting surface.