Serway & Jewett — The Laws of Motion: Problem 30

The person in Figure P5.30 weighs 170 lb. As seen from the front, each light crutch makes an angle of \(22.0^\circ\) with the vertical. Half of the person's weight is supported by the crutches. The other half is supported by the vertical forces of the ground on the person's feet. Assuming that the person is moving with constant velocity and the force exerted by the ground on the crutches acts along the crutches, determine (a) the smallest possible coefficient of friction between crutches and ground and (b) the magnitude of the compression force in each crutch.