FCTC Mechanical Reasoning Principles 5

Question 1

A firefighter must force open a door using a halligan bar. Placing the tool closer to the door's hinges rather than the latch will:

Accepted Answer

Reduce the mechanical advantage

Answer

Applying force closer to the fulcrum (hinge) reduces mechanical advantage, requiring more force to open the door.

Question 2

Two identical pumps are connected in series. Compared to a single pump, the combination will:

Accepted Answer

Double the pressure output

Answer

Pumps in series add their pressure outputs while maintaining the same flow rate as a single pump.

Question 3

A fire hose nozzle is narrowed to increase water velocity. This is an application of:

Accepted Answer

The Venturi effect / continuity equation

Answer

The continuity equation states that reducing cross-sectional area increases fluid velocity to maintain constant flow rate.

Question 4

A ladder truck extends its aerial ladder while the vehicle is parked on a slight side slope. The greatest risk is:

Accepted Answer

The vehicle tipping due to shifted center of gravity

Answer

Extending a heavy aerial ladder shifts the vehicle's center of gravity, and a side slope increases the risk of tipping.

Question 5

Which type of valve is BEST suited for precise throttling of water flow in a fire suppression system?

Accepted Answer

Globe valve

Answer

Globe valves are designed for throttling because their internal disc can be partially opened to regulate flow with precision.

FCTC Test Practice Test