Required for equilibrium:
Sum of forces = 0
Sum of the torques (moments) = 0
Our forces DOWN are:
Painter: 79.2 kg (F = MA = 79.2 kg * 9.8 m/s^2 = 776.16 N)
Platform: 18 kg (F =- MA = 18 * 9.8 m/s^2 = 176.4 N)
Total: 776.16 + 176.4 = 952.56 N DOWN ===> Total forces by the rope UP must also = 952.56 N
We take moments about the LEFT END ===> We can ignore the tension in the LEFT rope for the moment since it has no lever arm.
Painter Moment: 776.16 N * 2 m = 1552.32 N*m
Platform CG is mid-way: 176.4 N * 4.7/2 m = 414.54 N*m
Total: 1552.32 + 414.54 = 1966.86 N*m ClockWise
The RIGHT rope must counter that moment
Right rope = X N * 4.7 m = 1966.86
=> X = 418.5 N
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