#### Answer

0.61

#### Work Step by Step

To find the frictional force we need two quantities - the coefficient of friction and the Normal force. We are given the force of friction as 470N, so therefore Ff = N*mu where N is the normal force and mu is the coefficient. We can find the normal force by looking at the forces acting in the y direction and realizing that there are only two forces - the normal force and the weight of the man. Since the player is not accelerating in the y direction, the two must cancel and the Normal force is equal to the weight of the man. This is 79kg*9.8 = 774N. Then we know that this Normal force * mu = 470N and so mu = 470N/774N = 0.61