Levers Flashcards

Lever Definition and Function

• A lever is a simple machine made up of a solid bar that pivots around a fulcrum, facilitating the lifting of objects.
• Levers make work easier by requiring less force to move an object; this is achieved by increasing the distance over which the force is applied.

Types of Levers

• First Class Lever: Fulcrum is positioned between the effort and load (e.g., screwdriver opening a paint can, seesaw).
• Second Class Lever: Load is in the middle between the effort and fulcrum (e.g., wheelbarrow, nutcracker).
• Third Class Lever: Effort is applied between the fulcrum and load (e.g., sweeping with a broom).

Mechanical Advantage (MA)

• Mechanical Advantage (MA) for first and second class levers is calculated as the ratio of the effort arm to the load arm (Effort Arm / Load Arm or Fr/Fe).
• Third class levers do not have a significant mechanical advantage, as they typically require more effort than the load being lifted.

Examples of Levers

• First Class Lever: Both seesaws and screwdrivers demonstrate equal spacing of effort and load around the fulcrum.
• Second Class Lever: Load is lifted with less effort in tools like wheelbarrows and nutcrackers due to the positioning of the load.
• Third Class Lever: Use of a broom necessitates greater effort as the broomstick pivots at the end but requires significant force to move the load at the bristles.