Mechanical Aptitude Test Mechanical Aptitude Levers, Pulleys, and Gears 1 — Questions and Answers
Question 1: A lever has its fulcrum 2 feet from the load and 6 feet from the effort. If a 90-pound load is placed on the short end, how much effort is required to lift it?
- 30 pounds (Correct answer)
- 45 pounds
- 60 pounds
- 270 pounds
Correct answer: 30 pounds
Using the lever principle: Effort × effort arm = Load × load arm. So Effort × 6 = 90 × 2, giving Effort = 180 ÷ 6 = 30 pounds. The 3:1 mechanical advantage means one-third the force is needed.
Question 2: A fixed pulley attached to a ceiling is used to lift a 150-pound box. Ignoring friction, how much force must be applied to the rope?
- 75 pounds
- 100 pounds
- 150 pounds (Correct answer)
- 300 pounds
Correct answer: 150 pounds
A single fixed pulley only changes the direction of force — it provides no mechanical advantage. You must still exert a force equal to the full weight of the load, which is 150 pounds.
Question 3: A movable pulley is combined with a fixed pulley to create a simple block-and-tackle system. What is the mechanical advantage of this two-pulley arrangement?
- 1
- 2 (Correct answer)
- 3
- 4
Correct answer: 2
In a block-and-tackle with one fixed and one movable pulley, two rope segments support the movable pulley and its load, giving a mechanical advantage of 2. This means you lift with half the force the load weighs.
Question 4: Gear A has 15 teeth and meshes with Gear B, which has 45 teeth. If Gear A is the driver and turns at 600 RPM, in which direction does Gear B turn and at what speed?
- Same direction as A, at 1800 RPM
- Opposite direction to A, at 200 RPM (Correct answer)
- Same direction as A, at 200 RPM
- Opposite direction to A, at 1800 RPM
Correct answer: Opposite direction to A, at 200 RPM
Meshed gears always rotate in opposite directions. The gear ratio is 15:45 = 1:3, so Gear B turns at 600 ÷ 3 = 200 RPM. The larger gear turns slower and in the reverse direction.
Question 5: A first-class lever is 10 feet long. The fulcrum is placed 4 feet from the effort end. Where is the fulcrum relative to the load end, and what is the mechanical advantage?
- 6 feet from load; MA = 1.5 (Correct answer)
- 6 feet from load; MA = 0.67
- 4 feet from load; MA = 1.0
- 2 feet from load; MA = 2.0
Correct answer: 6 feet from load; MA = 1.5
If the lever is 10 feet long and the fulcrum is 4 feet from the effort, it is 6 feet from the load. Mechanical advantage = effort arm ÷ load arm = 4 ÷ 6 ≈ 0.67... wait — MA = load arm / effort arm is incorrect here. MA = effort arm / load arm = 6/4 = 1.5. The effort arm is the distance from effort to fulcrum (6 ft) and load arm is fulcrum to load (4 ft), giving MA = 6 ÷ 4 = 1.5.
Question 6: Which type of lever always produces a mechanical advantage greater than 1, regardless of where the effort is applied?
- First-class lever
- Second-class lever (Correct answer)
- Third-class lever
- All classes of lever
Correct answer: Second-class lever
In a second-class lever, the load is always positioned between the fulcrum and the effort. This means the effort arm is always longer than the load arm, so the mechanical advantage is always greater than 1. A wheelbarrow is a classic example.
Mechanical Aptitude Test Mechanical Aptitude Levers, Pulleys, and Gears 1
A lever has its fulcrum 2 feet from the load and 6 feet from the effort.
If a 90-pound load is placed on the short end, how much effort is required to lift it?