posted by Sam .
A sturdy wooden board, 4.0 meters long and with a mass of 32 kg, rests on two supports (labeled L and R) placed 1.2 m from each end as shown in the figure below.
(a) Suppose that a man with a mass of 60 kg stands at the center of the board (point a). What are the upward forces on the board from each support?
(b) Now the man stands 1.0 m from one end of the board (point b). What are the upward forces from each support now?
(c) The man edges gradually toward the end of the board. At what distance from the end does the board finally tip?
1. draw the figure, with forces.
2. Sum the vertical forces, and set to zero.
3. Sum moments about either end.
You will have the solution.