posted by chelsea on .
The drawing shows a person (weight W = 581 N, L1 = 0.843 m, L2 = 0.404 m) doing push-ups. Find the normal force exerted by the floor on each hand and each foot, assuming that the person holds this position.
force on each hand
force on each foot
without the drawing, ....
We have vertical and rotational equilibrium.
All vertical forces are balanced:
2•N1 +2•N2 –W = 0.
(N1+N2) = W/2.
The sum of torques around the feet are
W•L1 – 2•N2(L1+L2) = 0.
581•0.843 =2•N2• (0.843+0.404),
N2 =581•0.843/2• (0.843+0.404) =
N1+N2 =581/2= 290.5
N2 = 290.5-196.4=94.1 N