A man doing push-ups pauses in the position shown in the figure . His mass = 68 kg.

Image: img145.imageshack.us/img145/7130/picture1n.png

a= 40 cm
b= 95 cm
c= 30 cm

Determine the normal force exerted by the floor on each hand.

Determine the normal force exerted by the floor on each foot.

1 answer

Let Fl be the force upward on the hands, Fr be the force on his toes.

Fr+Fl=weight
Now sum moments about any point, I will sum them about the feet. Clockwise moments are postive. -weight*b+Fl*(a+b)=0

you have two equations, two unknowns (Fl,Fr). solve. Now for each hand,divide Fl by 2, and for each foot, divide Fr by 2.