FCTC FCTC Test Pulleys, Gears, and Levers Questions and Answers 5 — Questions and Answers
Question 1: A lever in equilibrium has a 50 lb load 4 feet from the fulcrum. How much effort is needed 10 feet from the fulcrum on the opposite side?
- 10 lbs
- 20 lbs (Correct answer)
- 40 lbs
- 125 lbs
Correct answer: 20 lbs
Using the lever equation: effort × 10 = 50 × 4, so effort = 200 ÷ 10 = 20 lbs.
Question 2: Which scenario correctly describes an idler gear in a gear train?
- It increases speed between the driver and driven gears
- It reverses the direction of rotation without changing the gear ratio (Correct answer)
- It reduces friction between gears
- It locks two gears together
Correct answer: It reverses the direction of rotation without changing the gear ratio
An idler gear placed between two gears reverses the direction of the driven gear without affecting the overall gear ratio.
Question 3: A snatch block is a type of pulley used in rigging. What makes it different from a standard pulley?
- It has a fixed axle only
- It can be opened to insert a rope without threading the end (Correct answer)
- It multiplies force by 10
- It is used only for horizontal loads
Correct answer: It can be opened to insert a rope without threading the end
A snatch block opens on the side so a rope can be inserted midway without needing access to the rope's end.
Question 4: If a first-class lever's effort arm equals its resistance arm, what is the mechanical advantage?
- 0
- 0.5
- 1 (Correct answer)
- 2
Correct answer: 1
When effort arm = resistance arm, MA = effort arm ÷ resistance arm = 1, so no force multiplication occurs.
Question 5: A worm gear set has a worm with 1 start and a worm wheel with 40 teeth. What is the gear reduction ratio?
- 1:1
- 1:20
- 1:40 (Correct answer)
- 40:1
Correct answer: 1:40
With a single-start worm, one full worm rotation advances the wheel by 1 tooth, so the ratio is 1:40.
Question 6: Which class of lever always has a mechanical advantage less than 1?
- First-class
- Second-class
- Third-class (Correct answer)
- All levers can have MA less than 1
Correct answer: Third-class
Third-class levers always have the effort between the fulcrum and load, making the effort arm shorter and MA always less than 1.
Question 7: In a pulley system, what effect does friction in the pulley bearings have on the system?
- It increases mechanical advantage
- It reduces actual mechanical advantage below the ideal value (Correct answer)
- It has no effect on the output
- It increases the load capacity
Correct answer: It reduces actual mechanical advantage below the ideal value
Bearing friction requires extra effort force, reducing the actual mechanical advantage below the theoretical ideal.
FCTC FCTC Test Pulleys, Gears, and Levers Questions and Answers 5
A lever in equilibrium has a 50 lb load 4 feet from the fulcrum.
How much effort is needed 10 feet from the fulcrum on the opposite side?