posted by Alexis .
When jumping straight down, you can be seriously injured if you land stiff-legged. One way to avoid injury is to bend your knees upon landing to reduce the force of the impact. A 75 kg man just before contact with the ground has a speed of 6.1 m/s. (a) In a stiff-legged landing he comes to a halt in 2.5 ms. Find the average net force that acts on him during this time. (b) When he bends his knees, he comes to a halt in 0.12 s. Find the average force now