Question

A young work crew is trying to quickly finish some touch-up painting to complete a job. Rather than setting up a secure work area, they decide to try a shortcut. Worker A will hold the far end of a 9.96 m work plank which weighs 111 N and is secured with a hinge on the opposite end. Worker B will stand on the plank 4.44 m from worker A. Worker B also brings up his paint can, mc = 3.54 kg, which he places 0.250 m from where he is standing on the plank (between the two workers). Worker A unfortunately needs to supply 496 N of force to hold the end of the plank. How much does worker B weigh? The acceleration due to gravity is g = 9.81 m/s2.

Answer 1

Weight of worker B,

Fb = [(Fa L) - w(L/2) - mg(L - (4.44 - 0.25))]/(L - 4.44)

Fb = [(496 x 9.96) - (111 x 9.96/2) - (3.54 x 9.8) (9.96 - 4.19)]/(9.96 - 4.44)

Fb = 758.55 N

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