FCTC Applying Mechanical Reasoning 2 โ Questions and Answers
Question 1: A lever is 10 feet long with the fulcrum placed 2 feet from the load end. To lift a 200-lb load, approximately how much force must be applied at the other end?
- 25 lb
- 50 lb (Correct answer)
- 100 lb
- 200 lb
Correct answer: 50 lb
With an 8-foot effort arm and 2-foot load arm, mechanical advantage is 4, so 200 รท 4 = 50 lb of force needed.
Question 2: Two gears mesh together. Gear A has 40 teeth and Gear B has 10 teeth. If Gear A rotates at 100 RPM, how fast does Gear B rotate?
- 25 RPM
- 100 RPM
- 250 RPM
- 400 RPM (Correct answer)
Correct answer: 400 RPM
Gear ratio = 40/10 = 4, so Gear B rotates 4 times faster: 100 ร 4 = 400 RPM.
Question 3: A block and tackle system has 4 rope segments supporting the load. If the load weighs 400 lb, how much pulling force is required (ignoring friction)?
- 50 lb
- 100 lb (Correct answer)
- 200 lb
- 400 lb
Correct answer: 100 lb
With 4 supporting rope segments, the mechanical advantage is 4, so 400 รท 4 = 100 lb of force is needed.
Question 4: A hydraulic press has an input piston with area 2 sq in and an output piston with area 20 sq in. If 50 lb of force is applied to the input, what force does the output exert?
- 5 lb
- 50 lb
- 250 lb
- 500 lb (Correct answer)
Correct answer: 500 lb
Hydraulic mechanical advantage = output area รท input area = 20/2 = 10, so output force = 50 ร 10 = 500 lb.
Question 5: A wedge is being driven into a log. What happens to the mechanical advantage if the wedge angle is made smaller (thinner wedge)?
- Mechanical advantage decreases
- Mechanical advantage increases (Correct answer)
- Mechanical advantage stays the same
- The wedge stops working
Correct answer: Mechanical advantage increases
A thinner wedge has a smaller angle, which increases mechanical advantage, making it easier to split the wood with less force.
Question 6: A screw has 20 threads per inch and a handle radius of 6 inches. What is its mechanical advantage?
- About 120
- About 377
- About 754 (Correct answer)
- About 1200
Correct answer: About 754
MA = 2ฯ ร handle radius ร threads per inch = 2ฯ ร 6 ร 20 โ 754.
Question 7: Which type of lever has the effort applied between the fulcrum and the load?
- First-class lever
- Second-class lever
- Third-class lever (Correct answer)
- Fourth-class lever
Correct answer: Third-class lever
A third-class lever has effort between the fulcrum and load, trading mechanical advantage for speed and range of motion.
FCTC Applying Mechanical Reasoning 2
A lever is 10 feet long with the fulcrum placed 2 feet from the load end.
To lift a 200-lb load, approximately how much force must be applied at the other end?