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
N
force on each foot
N
2 answers
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) =
=196.4 N.
N1+N2 =581/2= 290.5
N2 = 290.5-196.4=94.1 N
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) =
=196.4 N.
N1+N2 =581/2= 290.5
N2 = 290.5-196.4=94.1 N
1 answer