Question

Your mother asks you to carry a load of wood to the fireplace and lower it to the hearth. In doing this you have used your legs as levers. Which statement describes this as a class three lever?

Question 13 options:


A. The wood was the fulcrum, the load were was the knees, and the effort (input force) was supplied by your legs.


B. The wood was the load, the fulcrum was your knees, and the effort (input force was supplies by your leg muscles.


C. The fulcrum was the muscles in your legs, the load was the wood and the effort (input force) was the knees.

Answer 1

The answer is (B).

A class 3 lever can be described as when the fulcrum is the load; the effort (input force) is supplied by the muscles in your legs.

(A) is incorrect because the fulcrum is not the load in this scenario. (C) is also incorrect because the muscles in your legs don’t provide the effort (input force) in this example.