What is the coefficient of friction and magnitude of the compression force ?

Question

The person in Figure P4.51 weighs 190 lb. Each crutch makes an angle of = 22.0° with the vertical.
Half of the person's weight is supported by the crutches, the other half by the vertical forces exerted by the ground on his feet.
Assuming the person is at rest and the force exerted by the ground on the crutches acts along the crutches, determine each of the following.

1.) the smallest possible coefficient of friction between crutches and ground

2.) the magnitude of the compression force supported by each crutch

Answer 1

Go to this site
http://en.wikipedia.org/wiki/Friction