GED Science TestPhysical ScienceHard
A student is attempting to lift a heavy box using a lever. They place the fulcrum closer to the box and further from where they apply their effort. How does this arrangement affect the mechanical advantage of the lever?
- AIt only affects the speed at which the box is lifted.
- BIt increases the mechanical advantage.
- CIt has no effect on the mechanical advantage.
- DIt decreases the mechanical advantage.
Show answer & explanationAnswer & explanation
Correct answer: B. It increases the mechanical advantage.
Mechanical advantage (MA) of a lever is the ratio of the distance from the fulcrum to the effort to the distance from the fulcrum to the load. By placing the fulcrum closer to the load (box) and further from the effort, the effort arm length increases relative to the load arm length, thus increasing the mechanical advantage.
Why the other options are wrong
- A. While MA can affect the distance/speed, its primary effect is on the force required.
- C. The position of the fulcrum significantly changes the lengths of the effort and load arms, directly affecting MA.
- D. Placing the fulcrum closer to the load increases the effort arm relative to the load arm, thereby increasing MA.
Lever Mechanical Advantage
The mechanical advantage of a lever is the ratio of the output force (load) to the input force (effort), or the ratio of the effort arm length to the load arm length. It indicates how much a lever multiplies force.
- MA = Effort Arm Length / Load Arm Length.
- Higher MA means less effort force needed.
- Fulcrum position is key to determining MA.
Memory trick: Levers give an 'Advantage' by balancing arms.