The person weighs 170 lb. Each crutch makes an angle of 22.0with the vertical. Half of the person's weight is supported by thecruches, the other half by the vertical forces exerted by the roundon his feet. Assuming that he is at rest and that the force exertedby the ground on the crutches acts along the crutches,determine

a) the smallest possible coefficient of friction betweencrutches and ground and

b) the magnitude of the compression force supported by eachcrutch.

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## Answers ( 1 )

_{ground}=170/2 = 85lb)? Fy= 2F cos 22 +85lbs-170lbs

so F = 45.8lbs

from the second diagram

_{tip}- 45.8 cos 22=0 -------n tip = 42.5lbs_{tip}= 0.404