Biomechanical research has shown that when a 73 kilogram man is running, the force exerted on each foot as it strikes the ground is about 2400 Newton, straight up.
A) If the forces of the ground and the weight are the only forces exerted on this man. Determine the acceleration of the man.
B) If the man has a downward velocity of .85 m/s when his foot hits the ground, find the length of time that the 2400 Newton force must be exerted therefore that the vertical component of the velocity is reversed.