This exercise is a very common way to teach about impact, spacing and timing along a curve. Notice this is "bending" the speeding-up and slowing-down recipe along a curve.
This is used when animating a frog, a ball, a football, a bicycle jump, and many other things that change direction after colliding with something.
Why Is This Important?
Impacts and showing motion along a curve is common in all animation. Things change directions after colliding, and the bouncing ball teaches the skill of crafting the illusion of impact and momentum. It is a classic in animation instruction. Mastering the bouncing ball is a must because the dynamics involved are used in so many other places in animation.
