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Homework Help: Whats wrong with this torque set up

  1. Jan 1, 2005 #1
    The problem involves a man doing push ups, he weighs 70 KG. It wants to know the force on each hand and each foot. His center of gravity is 25 cm from his two hands, and 73 cm from his feet. The center of gravity is also 30 cm above both is hands and feet.

    Using the hands as the rotation point, weight bearing down negative, force of the ground on the feet upwards

    Sum of the torque equals 0 = (-70)(9.8)(.25) + (.98)(Force of Feet)

    This comes out to be 175 N, which I know is incorrect, but do not see what is wrong with the set up. Obviously the hands should be bearing a decent amount more than the feet.
  2. jcsd
  3. Jan 1, 2005 #2
    175 N on the feet and 511 N for the Hands 511N>175N your work is right
  4. Jan 1, 2005 #3
    Ah, stupid book must have rounded a lot, thats why I thought I was off, thanks, so the 30 cm was useless info
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