Mechanical Aptitude MCQ Questions and Answers 3

Question 1

What type of stress occurs when a material is pulled apart?

Accepted Answer

Tensile stress

Answer

Tensile stress occurs when forces act to stretch or pull apart a material. It is calculated as force per unit area (σ = F/A) and is the opposite of compressive stress, which pushes material together.

Question 2

What is the primary purpose of a differential in a vehicle?

Accepted Answer

To allow wheels to rotate at different speeds during turns

Answer

A differential allows the outer wheel to rotate faster than the inner wheel during turns, preventing tire scrubbing and maintaining traction. Without a differential, both drive wheels would be forced to turn at the same speed, causing handling problems in curves.

Question 3

Which type of thread has a V-shaped profile and is most common for fasteners?

Accepted Answer

Metric/Unified thread

Answer

Metric (ISO) and Unified (UNC/UNF) threads have a 60° V-shaped profile and are the most common thread types for nuts, bolts, and screws. Square and Acme threads are used for power transmission, and buttress threads resist force in one direction.

Question 4

What does a thermostat do in a cooling system?

Accepted Answer

Regulates coolant flow based on temperature

Answer

A thermostat is a temperature-sensitive valve that regulates coolant flow through the cooling system. It remains closed when the engine is cold (allowing faster warm-up) and opens progressively as temperature rises to allow coolant to flow through the radiator.

Question 5

What mechanical advantage does a screw provide?

Accepted Answer

Conversion of rotational force into large linear force

Answer

A screw converts rotational motion into linear motion with high mechanical advantage. The closer together the threads (finer pitch), the greater the mechanical advantage — a small input torque generates a very large linear pushing or pulling force.

Mechanical Aptitude Test Practice Test

Mechanical Aptitude Test Practice Test

Mechanical Aptitude MCQ Questions and Answers 3