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Homework Help: Pressure of Crutches

  1. May 2, 2012 #1
    1. The problem statement, all variables and given/known data

    A 72 kg person sits on a 4.0 kg chair. Each leg of the chair makes contact with the floor in a circle that is 1.1 cm in diameter. Find the pressure exerted on the floor by each leg of the chair, assuming the weight is equally distributed.

    2. Relevant equations


    3. The attempt at a solution

    To find the force, I added the mass of the person and the mass of the chair and got m=76kg. Then i multiplied that by g=9.81 and got F=745.56.
    To find the area, I converted 1.1 cm into meters, .011, and found the area A=9.5*10^-5
    then i divided F/A and got P=7845260 but this is incorrect.
  2. jcsd
  3. May 2, 2012 #2


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    Science Advisor

    Okay, that's good.

    Did you recall that the chair has four legs? Oh, and be sure to include units of measurement.
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