ASVAB Mechanical Comprehension 4

Question 1

A screw has 20 threads per inch. How far does it advance per complete revolution?

Accepted Answer

0.05 inches

Answer

Advance per revolution = 1 ÷ threads per inch = 1 ÷ 20 = 0.05 inches.

Question 2

Which simple machine is essentially an inclined plane wrapped around a cylinder?

Accepted Answer

Screw

Answer

A screw is an inclined plane (ramp) wound helically around a cylindrical shaft.

Question 3

If a 10 kg box is pushed across a floor with a coefficient of kinetic friction of 0.3, what is the friction force? (g = 10 m/s²)

Accepted Answer

30 N

Answer

Friction force = μ × N = 0.3 × (10 × 10) = 30 N.

Question 4

In a compound pulley system with 4 rope segments supporting the load, what is the mechanical advantage?

Accepted Answer

4

Answer

Mechanical advantage of a pulley system equals the number of rope segments supporting the load.

Question 5

Which valve type is best suited for fully open or fully closed flow control, not for throttling?

Accepted Answer

Gate valve

Answer

Gate valves are designed for on/off service and should not be used for throttling as the gate can vibrate and erode.

ASVAB - Armed Services Vocational Aptitude Battery Practice Test