## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

The sum of the four friction forces is equal in magnitude to the weight of the gymnast. So, $4~F_f = mg$ $F_f = \frac{mg}{4}$ $F_f = \frac{(65~kg)(9.80~m/s^2)}{4}$ $F_f = 160~N$ The magnitude of the friction force on each hand and foot is 160 N.