Mechanical Aptitude Simple Machines and Mechanical Advantage Questions and Answers 2

Question 1

A screw has 8 threads per inch. How far does it advance into a material with one complete revolution?

Accepted Answer

0.125 inches

Answer

The pitch (advance per revolution) equals 1 divided by threads per inch: 1 ÷ 8 = 0.125 inches.

Question 2

What is the ideal mechanical advantage of a single movable pulley?

Accepted Answer

2

Answer

A single movable pulley has a mechanical advantage of 2 because two rope segments support the load, halving the required effort.

Question 3

An inclined plane with a mechanical advantage of 5 requires 40 lbs of input force. What load can it raise?

Accepted Answer

200 lbs

Answer

Output force = Mechanical advantage × Input force = 5 × 40 = 200 lbs.

Question 4

Machine efficiency is calculated as:

Accepted Answer

Output work ÷ Input work × 100%

Answer

Efficiency = (Output work ÷ Input work) × 100%; a perfect machine would be 100% efficient, but friction always reduces this.

Question 5

A doorknob is an example of which simple machine?

Accepted Answer

Wheel and axle

Answer

A doorknob is a wheel and axle — the large knob is the wheel and the spindle (latch shaft) is the axle, multiplying torque.

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