Question

When a gymnast performed a vault during competition, she was in contact with the takeoff board for 0.8 s. The vault involved a forward somersault.

a. Did the line of action of the ground reaction force pass in front of or behind her center of mass for most of the takeoff phase? Why?
b. The ground reaction force had an average value of 1200 N during the takeoff phase, which resulted in a net angular impulse of 209 N·m·s. What was the average value of the moment arm? Which moment arm was this?

Answer 1