FCTC FREE FCTC Test Mechanical Reasoning Principles Questions and Answers 3 — Questions and Answers
Question 1: A wrench with a 12-inch handle requires 30 ft-lbs of torque to turn a bolt. If you switch to an 18-inch handle wrench, how much force is needed to produce the same torque?
- 20 lbs (Correct answer)
- 30 lbs
- 45 lbs
- 60 lbs
Correct answer: 20 lbs
Torque = Force × Length; 30 ft-lbs ÷ 1.5 ft = 20 lbs of force needed with the longer handle.
Question 2: Water flows through a pipe that narrows from 4 inches in diameter to 2 inches. How does the water's speed change at the narrower section?
- It doubles
- It quadruples (Correct answer)
- It halves
- It stays the same
Correct answer: It quadruples
Because the cross-sectional area decreases by a factor of 4 (area ∝ diameter²), the velocity must increase by a factor of 4 to maintain continuity.
Question 3: A steel spring is compressed 3 inches by a 60-lb force. How much force is required to compress it 5 inches?
- 36 lbs
- 60 lbs
- 100 lbs (Correct answer)
- 120 lbs
Correct answer: 100 lbs
Hooke's Law: k = 60 ÷ 3 = 20 lb/in; force at 5 in = 20 × 5 = 100 lbs.
Question 4: Two gears mesh together. Gear A has 40 teeth and Gear B has 10 teeth. If Gear A turns at 100 RPM, what is Gear B's speed?
- 25 RPM
- 40 RPM
- 250 RPM
- 400 RPM (Correct answer)
Correct answer: 400 RPM
Gear ratio = 40:10 = 4:1, so Gear B turns 4 times faster: 100 × 4 = 400 RPM.
Question 5: A hydraulic jack has an input piston with a 2 sq-in area and an output piston with a 20 sq-in area. If you apply 50 lbs on the input, what load can the output lift?
- 5 lbs
- 50 lbs
- 250 lbs
- 500 lbs (Correct answer)
Correct answer: 500 lbs
Pascal's Law: Output force = Input force × (Output area ÷ Input area) = 50 × (20 ÷ 2) = 500 lbs.
Question 6: A ball rolls off a level table and falls to the floor. Which path best describes its trajectory?
- Straight vertical drop
- Straight horizontal path
- Curved parabolic arc (Correct answer)
- Circular arc
Correct answer: Curved parabolic arc
The ball maintains horizontal velocity while gravity accelerates it downward, producing a parabolic trajectory.
Question 7: Which material would best conduct heat away from an engine's cylinder head?
- Rubber
- Fiberglass
- Aluminum (Correct answer)
- Plastic
Correct answer: Aluminum
Aluminum has high thermal conductivity (~205 W/m·K), making it ideal for heat dissipation in engine components.
FCTC FREE FCTC Test Mechanical Reasoning Principles Questions and Answers 3
A wrench with a 12-inch handle requires 30 ft-lbs of torque to turn a bolt.
If you switch to an 18-inch handle wrench, how much force is needed to produce the same torque?