FAA Aviation Mechanic General (AMG)Physics, Math and Fluid LinesMedium
A lever has an effort arm of 24 inches and a resistance arm of 6 inches. If an effort force of 50 pounds is applied, what resistance force can the lever overcome?
- A100 lb
- B150 lb
- C200 lb
- D50 lb
Show answer & explanationAnswer & explanation
Correct answer: C. 200 lb
Mechanical advantage = effort arm ÷ resistance arm = 24 ÷ 6 = 4. Resistance force = effort force × mechanical advantage = 50 × 4 = 200 lb.
Why the other options are wrong
- A. This uses a mechanical advantage of 2 instead of 4.
- B. This does not match the correct multiplication.
- D. This is simply the effort force with no mechanical advantage applied.
Lever Mechanical Advantage
A lever multiplies force based on the ratio of the effort arm length to the resistance arm length.
- MA = effort arm ÷ resistance arm
- Resistance force = effort force × MA
- Longer effort arm relative to resistance arm increases force multiplication
Memory trick: Longer effort arm, bigger payoff on the short side.