Question

A 5-meter uniform plank of mass 100 kilograms rests on the top of a building with 2 meters extended over the edge as shown above. how far can a 50-kilogram person venture past the edge of the building on the plank before the plank just begins to tip?

Answer 1

To calculate how far the person can walk, we compute for the tipping point where: tccw = tcw
tau - plank = tau - person

r1 F1 = r2 F2

r1 m1 = r2 m2

(0.5 m) (100 kg) = r2 (50)

r2 = 1 m is how far the venture past the edge of the building on the plank before the plank just starts to tip.