Question

Explain the following text primarily based on the surrounding page content:
With which class of levers is it possible to increase the force that must be applied?(1 point)
Responses

Class 2 and 3
Class 2 and 3

Class 1 and 3
Class 1 and 3

Class 1 and 2
Class 1 and 2

Class 3 and 4
Class 3 and 4

Answer 1

Answer: Class 1 and Class 3.

Why: Whether a lever makes you apply more or less force depends on the lever arms (distance from fulcrum). Using torque balance (effort × effort arm = load × load arm), if the effort arm is shorter than the load arm you must apply a larger force than the load.

- Class 3 levers (effort between fulcrum and load, e.g. tweezers, human forearm) always have a shorter effort arm than load arm, so they always require a larger applied force (mechanical disadvantage).
- Class 1 levers (fulcrum between effort and load, e.g. seesaw) can be arranged either way; if the effort arm is shorter than the load arm they will also require a larger applied force — so it is possible with class 1 to increase the needed force.
- Class 2 levers (load between fulcrum and effort, e.g. wheelbarrow) always give a mechanical advantage (less effort required), so they cannot increase the required input force.

(“Class 4” is not a standard simple-lever class.)