SkyDrill

First class lever effort calculation

Aviation Mechanic General (AMG) practice question 3 of 20 on Physics for Aviation. ACS element AM.I.J.K2 · difficulty: applied. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONA first class lever is used to lift a 600-lb weight. The weight is 10 inches from the fulcrum and the effort is applied 40 inches from the fulcrum. How much effort is required?

  1. A150 lb
  2. B240 lb
  3. C2,400 lb
Show the answer and explanation

Correct answer: A. 150 lb

  • A — correct Effort × Effort Arm = Resistance × Resistance Arm. E × 40 in = 600 lb × 10 in, so E = 6,000 ÷ 40 = 150 lb.
  • B — incorrect This figure does not come from the lever formula. Dividing 600 lb × 10 in by the 40-in effort arm gives 150 lb.
  • C — incorrect Multiplying 600 lb by 40 in and dividing by 10 in reverses the arms. The longer arm belongs to the effort, which reduces the force required.

BACKGROUND

A lever has three basic parts: the fulcrum, the effort, and the resistance. The distances from the fulcrum to the effort and to the resistance are the lever arms. In a first class lever the fulcrum lies between the effort and the resistance, as on a seesaw, crowbar, or pliers. The governing formula is Effort × Effort Arm = Resistance × Resistance Arm, which states that input torque equals output torque. Increasing the effort arm relative to the resistance arm increases the mechanical advantage.

STUDY TIP

Set up the equation as input torque equals output torque, then solve for the unknown. A longer effort arm always means less effort is needed.

KEY POINTS

  • Effort × Effort Arm = Resistance × Resistance Arm
  • Fulcrum between effort and resistance defines a first class lever
  • Mechanical advantage = Force Out ÷ Force In

SOURCES

  • FAA-H-8083-30B ch05 "First Class Lever"
Practice the Aviation Mechanic General (AMG) test →Timed 60-question exam, by ACS area, or review your misses. Free.
MORE ON PHYSICS FOR AVIATION

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.