Bouncing Balls Light and Heavy
The ball on the left worked very well as it demonstrates weight and good timing. The fast fall also contributes to the efficient animation of the heavy ball. The lighter ball on the other side has a very good beginning as it is rotating more easily and the fall is pretty slow compared to the other one. But the issue is in the very end when the ball bounces of the ground. The timing of the bounces can definitely be improved.
Maya Animation Tutorial for Beginners - Graph Editor