A physics student is about to do a pushup. Her center of mass lies above a point on the floor which is d1 = 1.01 m from her feet and d2 = 0.65 m from her hands. If her mass is 45.0 kg, what is the magnitude of the force exerted by the floor on her feet? (Neglect friction in this problem)(adsbygoogle = window.adsbygoogle || []).push({});

I don't think i know where to put the pivot in this problem. I tried a few times at the center of gravity.

Also I don't know what the "mass" of her feet are is it just (1.01/1.66)*45?

That's what i did then, once i just tried to find the Normal force with just that.

The next time I tried , I used the same method with the "mass" of her feet and hands, and then tried to find the torques. Her feet had a larger torque, so I subtracted the torque of her hands, and then divided by 1.01 to try and find the Normal force against her feet.. That didn't work either..

Anyone have a better approach?

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# Homework Help: Force exerted by the floor on the feet of a student doing pushups

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