CPS Firefighter Test Mechanical Aptitude and Principles Questions and Answers Flashcards

A firefighter applies 50 lbs of force to a wheel with a 12-inch radius attached to an axle with a 3-inch radius. What force is exerted at the axle?

Answer: 200 lbs

Mechanical advantage of wheel and axle = wheel radius ÷ axle radius = 12 ÷ 3 = 4, so output force = 50 × 4 = 200 lbs.

When a firefighter uses a screwdriver, which simple machine principle is being applied?

Answer: Wheel and axle

A screwdriver applies the wheel and axle principle — the wide handle acts as the wheel and the shaft acts as the axle, multiplying torque.

A firefighter's pike pole is used to pull down a ceiling. If it is used as a lever with a fulcrum at the shoulder (2 ft from effort, 6 ft from load), what is the mechanical advantage?

Answer: 0.33

Mechanical advantage = effort arm ÷ load arm = 2 ÷ 6 = 0.33, meaning more force is needed than the load but greater range of motion is gained.

Which factor most directly determines the pressure at the bottom of a water tank used for fire suppression?

Answer: Height of the water column

Hydrostatic pressure depends solely on the height of the fluid column: P = ρgh, so only the water height matters, not volume or tank shape.

A firefighter uses an inclined plane (ramp) to load equipment into a truck. The ramp is 10 feet long and raises the load 2 feet. What is the mechanical advantage?

Answer: 5

Mechanical advantage of an inclined plane = length of slope ÷ height = 10 ÷ 2 = 5.

Two springs are connected in parallel supporting a load. If each spring has a constant of 100 lb/in, what is the combined spring constant?

Answer: 200 lb/in

Springs in parallel add their constants directly: k_total = k1 + k2 = 100 + 100 = 200 lb/in.