The load L a horizontal beam can safely support varies jointly as the width w and the square of the depth d and inversely as the length l . If a 16-foot beam with width 7 inches and depth 15 inches safely supports 272 pounds, how many pounds can a 20-foot beam that has width 8 inches and depth 9 inches be expected to support? Round to the nearest pound. Assume the two beams are made of the same material.
A)184 lbs
B)559 lbs
C)89 lbs
D)79 lbs
E)73 lbs

Question

Quizplus · Accepted Answer

The load L is given by the formula L = k * (w * d^2) / l. First, find the constant k using the given values: 272 = k * (7 * 15^2) / 16. Solve for k, then use it to find the load for the second beam: L = k * (8 * 9^2) / 20. Calculate and round to the nearest pound.

The Load L a Horizontal Beam Can Safely Support Varies