Question

a colleague needs to move a 500 pound object that's on a lever. the fulcrum is 6 inches from the object. If your colleague weighs 180 pounds how far will your colleague need to be from the fulcrum to move the object? Use the formula B = (P x A) ÷ W, and round your answer to two decimal places.

Answer 1

Explanation:

The easier way to figure this is by using the concept of torque in physics. If the torque of the man is greater than that experienced by the box, the lever will tilt in the man's favor (in other words, he will move down and the box will be lifted). Torque is found by multiplying the perpendicular force by the length of the lever arm. Because we want the man's torque to be greater than the box's torque, the inequality is:

`\tau_(man)>\tau_(box)` and

`180r>500(.1524)` That decimal is 6 inches in terms of meters.

180r > 76.2 so

r > .42 meters or `16.67 inches. The man has to sit at a distance greater than 16.67 inches in order for the box to be lifted by the lever.