Shape tweens

Motion tween rules
Shape tween rules

Bob launched with rubber band

New layer band

Make bob layer ouotlines

Rectangle no stroke set color for band
Draw rubber band behind bob and across both sides

Add shape tween

Get green frames dotted line

Move playhead to frame 30.
Insert keyframe on band layer

Get curve on black arrow drac down middle of band

At the end we want the rubber band to snap to its original position. The quickest way to do that is to copyframe 1

Paste the keyframeat frame 33.