Mechanical Aptitude Mechanical Aptitude Levers, Pulleys, and Gears Questions and Answers 2 — Questions and Answers
Question 1: A worker uses a 4-foot crowbar to pry up a heavy crate, placing the fulcrum 1 foot from the load end. If the crate weighs 200 pounds, approximately how much force must the worker apply at the other end?
- About 67 pounds (Correct answer)
- About 100 pounds
- About 150 pounds
- About 200 pounds
Correct answer: About 67 pounds
With the fulcrum 1 foot from the load, the effort arm is 3 feet, so the mechanical advantage is 3:1, meaning roughly 67 pounds of effort moves 200 pounds.
Question 2: In a compound pulley system with 4 supporting ropes, how much force is theoretically needed to lift a 400-pound load?
- 100 pounds (Correct answer)
- 200 pounds
- 50 pounds
- 400 pounds
Correct answer: 100 pounds
A compound pulley with 4 supporting ropes provides a mechanical advantage of 4, so 400 divided by 4 equals 100 pounds of effort.
Question 3: Two meshed gears have 20 teeth and 60 teeth respectively. If the smaller gear rotates at 300 RPM, how fast does the larger gear turn?
- 100 RPM (Correct answer)
- 150 RPM
- 200 RPM
- 900 RPM
Correct answer: 100 RPM
The gear ratio is 60:20 or 3:1, so the larger gear turns at 300 divided by 3, which equals 100 RPM.
Question 4: Which class of lever has the effort applied between the fulcrum and the load?
- Third-class lever (Correct answer)
- First-class lever
- Second-class lever
- None of the above
Correct answer: Third-class lever
A third-class lever places the effort between the fulcrum and the load, such as a pair of tweezers or a fishing rod.
Question 5: A fixed pulley is attached to a ceiling and used to lift a 50-pound box. What is the primary advantage of this setup?
- It changes the direction of the force so you can pull downward (Correct answer)
- It reduces the effort needed to half
- It doubles the speed of lifting
- It eliminates friction entirely
Correct answer: It changes the direction of the force so you can pull downward
A single fixed pulley provides no mechanical advantage but allows you to pull downward using your body weight instead of lifting upward.
Question 6: In a gear train, if Gear A drives Gear B and Gear B drives Gear C, and all three gears are on separate shafts, which direction does Gear C rotate relative to Gear A?
- The same direction as Gear A (Correct answer)
- The opposite direction of Gear A
- It depends on the number of teeth
- Gear C does not rotate
Correct answer: The same direction as Gear A
Each meshed gear pair reverses direction, so after two reversals (A to B, then B to C), Gear C rotates in the same direction as Gear A.
Mechanical Aptitude Mechanical Aptitude Levers, Pulleys, and Gears Questions and Answers 2
A worker uses a 4-foot crowbar to pry up a heavy crate, placing the fulcrum 1 foot from the load end.
If the crate weighs 200 pounds, approximately how much force must the worker apply at the other end?