Mechanical Aptitude Mechanical Aptitude Principles 3

Question 1

A pulley system has one fixed and one movable pulley. How much force is needed to lift a 240 lb load?

Accepted Answer

120 lbs

Answer

A compound pulley with one movable pulley provides a mechanical advantage of 2, so force needed is 240/2 = 120 lbs.

Question 2

What is the primary purpose of a bearing in a rotating machine?

Accepted Answer

Reduce friction between moving parts

Answer

Bearings reduce friction between the rotating shaft and stationary housing, improving efficiency and life.

Question 3

A spring with a constant of 50 N/m is compressed by 0.2 m. What force does it exert?

Accepted Answer

10 N

Answer

Hooke's Law: F = k × x = 50 × 0.2 = 10 N.

Question 4

Which of the following is an example of a third-class lever?

Accepted Answer

Tweezers

Answer

In a third-class lever the effort is between the fulcrum and load; tweezers fit this description.

Question 5

Water flows through a pipe that narrows from 4 inches to 2 inches in diameter. What happens to the water's speed?

Accepted Answer

It quadruples

Answer

Area decreases by a factor of 4 (diameter halved), so velocity must quadruple to maintain flow rate (continuity equation).

Mechanical Aptitude Test Practice Test