## Conceptual Physics (12th Edition)

The scaffold is in equilibrium, and the sum of the forces on it is zero. The upward forces are 800 N and the unknown x. The downward forces are 500 N from the first painter, 400 N due to the weight of the scaffold, and 400 N from the second painter. $$800 N + x - 500 N - 400 N - 400 N = 0$$ $$x = 500 N$$