ASVAB Mechanical Comprehension Test 5

Question 1

A square-threaded screw has a pitch of 0.25 inches (advances 0.25 in per turn). If a 12-inch handle is used to turn it, what is the ideal mechanical advantage?

Accepted Answer

About 301

Answer

MA of a screw = 2π × handle length / pitch = 2π × 12 / 0.25 ≈ 301.

Question 2

Which type of stress acts perpendicular to the cross-section of a structural member and tends to pull it apart?

Accepted Answer

Tensile stress

Answer

Tensile stress acts perpendicular to a cross-section in a pulling direction, stretching the material.

Question 3

A centrifugal pump moves fluid by spinning an impeller. If the impeller's rotational speed doubles, by approximately what factor does the pump's pressure output increase?

Accepted Answer

4 times

Answer

Pump affinity laws state that pressure (head) varies as the square of rotational speed: doubling speed quadruples pressure.

Question 4

A weight hangs from two ropes attached to the ceiling. Rope A makes a 30° angle with the vertical and Rope B is vertical. Which rope carries more tension?

Accepted Answer

Rope A

Answer

The angled rope must support both its share of vertical load and provide a horizontal component, giving it greater total tension than the vertical rope.

Question 5

A hydraulic press has an input cylinder with a 1-inch diameter and an output cylinder with a 5-inch diameter. If the input piston moves down 10 inches, how far does the output piston move?

Accepted Answer

0.4 inches

Answer

Volume is conserved: π(0.5)²×10 = π(2.5)²×d, solving gives d = 10×(0.25/6.25) = 0.4 inches.

ASVAB - Armed Services Vocational Aptitude Battery Practice Test

ASVAB - Armed Services Vocational Aptitude Battery Practice Test

ASVAB Mechanical Comprehension Test 5