3. In 1990, Gary Stewart of California made 177 737 jumps on a pogo Stick. Suppose that the pogo stick reaches a height of 12.0 cm with each
jump and that the average net force acting on the pogo stick during the
contact with the ground is 330 N upward. What is the time of contact
with the ground between the jumps? Assume the total mass of Stewart
and the pogo stick is 65 kg. (Hint: The difference between the initial
and final velocities is one of direction rather than magnitude.)