A uniform beam 1 m in length is supported at its center by a fulcrum. A mass of 20kg is placed at the left end, a mass of 8kg is placed on the beam 10 m from the left end, and a third mass is placed 4 m from the right end. What mass should the third mass be to achieve equilibrium?
A) 28kg
B) 36kg
C) 16kg
D) 20kg
E) 10kg

Question

Quizplus · Accepted Answer

The beam is 1 m long, so the 8 kg mass cannot be placed 10 m from the left end. Assuming the beam is longer, the torque balance equation is: (20 kg * 0.5 m) + (8 kg * 9 m) = (x kg * 0.5 m). Solving for x gives 36 kg.

A Uniform Beam 1 M in Length Is Supported at Its