The person weighs 170 lb. Each crutch makes an ang...

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.

    Answers ( 1 )

    1. isabella gutierrez
      isabella gutierrez
      freebody diagram of the person
      free body diagram of cruches
      from the first diagram   (n ground =170/2 = 85lb)
      ? Fx= F1 sin22- F2 sin22 =0
      ? Fy= 2F cos 22 +85lbs-170lbs
      so F = 45.8lbs

      from the second diagram
      ? Fx= f - 45.8lbs sin22 =0 -----  f =17.2lbs
      ? Fy=n tip - 45.8 cos 22=0 -------n tip = 42.5lbs
      for minimum coefficient of friction
         ? = f / ntip = 0.404
      b)compressing force F =45.8lbs.

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