Question

A uniform plank of length 6.1 m and mass 33 kg rests horizontally on a scaffold, with 1.6 m of the plank hanging over one end of the scaffold. L l x How far can a painter of mass 60 kg walk on the overhanging part of the plank x before it tips? The acceleration of gravity is 9.8 m/s 2 . Answer in units of m.

Answer 1

Step-by-step explanation:

consider the principle of moment

when a system is in equilibrium, the clockwise moment (torque) about the pivot is equal to the counterclockwise moment ( torque). Since the plank is uniform the weight of the plank act at the middle which = 6.1 m / 2 = 3.05 m

the distance that can support the weight of the man = d

mass of the man = 70

70 × d = 33 × ( 3.05 - 1.6)

d = 47.85 / 60 = 0.798 m, if the man work beyond this point he will fall.