WTMA Aptitude Knowledge 3 — Questions and Answers
Question 1: Two gears mesh together. Gear A has 40 teeth and rotates at 100 RPM. Gear B has 20 teeth. How fast does Gear B rotate?
- 50 RPM
- 100 RPM
- 200 RPM (Correct answer)
- 400 RPM
Correct answer: 200 RPM
Gear speed ratio is inversely proportional to tooth count: 100 × (40 ÷ 20) = 200 RPM for Gear B.
Question 2: A hydraulic jack has an input piston area of 2 sq in and an output piston area of 20 sq in. A 50 lb force on the input produces what output force?
- 5 lb
- 50 lb
- 500 lb (Correct answer)
- 1000 lb
Correct answer: 500 lb
Pascal's Law: output force = input force × (output area ÷ input area) = 50 × (20 ÷ 2) = 500 lb.
Question 3: Which class lever has the fulcrum located between the effort and the load?
- Class 1 (Correct answer)
- Class 2
- Class 3
- Class 4
Correct answer: Class 1
A Class 1 lever has the fulcrum between the effort and load, like a seesaw or crowbar.
Question 4: When two resistors of 6 ohms each are connected in parallel, the total resistance is:
- 12 ohms
- 6 ohms
- 3 ohms (Correct answer)
- 1 ohm
Correct answer: 3 ohms
Parallel resistors: 1/R = 1/6 + 1/6 = 2/6, so R = 3 ohms.
Question 5: A ramp is 12 feet long and 3 feet high. What is its mechanical advantage?
- 4 (Correct answer)
- 3
- 9
- 36
Correct answer: 4
Mechanical advantage of an inclined plane = length ÷ height = 12 ÷ 3 = 4.
Question 6: Which material has the highest thermal conductivity and would transfer heat fastest?
- Wood
- Plastic
- Copper (Correct answer)
- Glass
Correct answer: Copper
Copper is an excellent thermal conductor, transferring heat far faster than wood, plastic, or glass.
Question 7: A ball rolls off a horizontal table. Which force causes it to curve downward toward the ground?
- Friction
- Gravity (Correct answer)
- Air resistance
- Normal force
Correct answer: Gravity
Gravity acts downward on the ball, curving its path downward while its horizontal velocity continues from the table's edge.
WTMA Aptitude Knowledge 3
Two gears mesh together.
Gear A has 40 teeth and rotates at 100 RPM.
Gear B has 20 teeth.
How fast does Gear B rotate?