CPS Firefighter Test Mechanical Aptitude and Principles Questions and Answers Flashcards

A firefighter needs to move a heavy hose reel using a lever. If the effort arm is 4 feet and the load arm is 1 foot, what is the mechanical advantage?

Answer: 4

Mechanical advantage of a lever equals effort arm length divided by load arm length: 4 ÷ 1 = 4.

Water flows through a 4-inch diameter pipe and enters a 2-inch diameter pipe. How does the water velocity change?

Answer: It quadruples

When pipe diameter is halved, the cross-sectional area decreases by a factor of 4, so velocity quadruples to maintain constant flow rate.

Which type of pulley system provides a mechanical advantage greater than 1 by using multiple sheaves?

Answer: Block and tackle

A block and tackle system uses multiple pulleys to multiply force, providing a mechanical advantage proportional to the number of rope segments supporting the load.

A firefighter climbs a ladder leaning against a building. As the ladder angle decreases (becomes more horizontal), the force at the base of the ladder:

Answer: Increases

As a ladder becomes more horizontal, the horizontal thrust at the base increases because more force is directed outward rather than downward.

In a hydraulic system, a small piston with area 2 sq in applies 100 lbs of force. What force does a large piston with area 10 sq in exert?

Answer: 500 lbs

Pascal's Law states pressure is equal throughout; pressure = 100/2 = 50 psi, so force on large piston = 50 × 10 = 500 lbs.

A gear with 12 teeth drives a gear with 36 teeth. If the drive gear rotates at 90 RPM, what is the speed of the driven gear?

Answer: 30 RPM

Gear ratio = 36/12 = 3, so the driven gear rotates at 90 ÷ 3 = 30 RPM.