Calculating the Upward Force Necessary to Balance a Plank

[gtaylor]

A uniform plank us supported by a hinge at one end. What is the magnitude (expressed as a multiple of the plank's weight Fg) of the upward force you have to exert on the other end to keep the plank at rest and level?

 

[kuruman]

The sum of all the forces must be zero and the sum of all the torques must be zero. Go for it.