Question

A person carries a plank of wood 2.00 m long with one hand pushing down on it at one end with a force F, and the other hand holding it up at .500 m from the other end of the plank with force F2 . If the plank has a mass of 20.0 kg and its center of gravity is at the middle of the plank, what are the magnitudes of the forces F, and F? F1 = 196 N; F2= 392 N

Answer 1

Taking Moment about the end where F2 acts  :

$\Rightarrow \left | F_1 \right | = mg = 20 * 9.8 = 196 N$

Taking Moment about the end where F1 acts  :

$\Rightarrow \left | F_2 \right | = \frac{mg}{0.5} = \frac{20 * 9.8 }{0.5}= 392 N$