CPS Mechanical Aptitude Principles 5

Question 1

A gear train has a driver of 12 teeth meshed with a 36-tooth gear, which is on the same shaft as a 12-tooth gear driving another 36-tooth gear. What is the overall speed reduction?

Accepted Answer

9 to 1

Answer

Each stage reduces speed 3:1, and two stages multiply to 9:1.

Question 2

Friction between two surfaces generally does what to motion?

Accepted Answer

Opposes motion

Answer

Friction is a resistive force that always opposes the relative motion of surfaces.

Question 3

Which arrangement gives a wrench the most turning power on a stubborn bolt?

Accepted Answer

A longer handle

Answer

A longer handle increases the lever arm, producing more torque for the same force.

Question 4

Hot air rises primarily because it is what compared to cold air?

Accepted Answer

Less dense

Answer

Heated air expands and becomes less dense, so it rises above cooler, denser air.

Question 5

A cam on a rotating shaft is typically used to do what?

Accepted Answer

Convert rotary motion into reciprocating (up-and-down) motion

Answer

A cam's irregular shape converts rotation into back-and-forth linear motion of a follower.

CPS Firefighter Test Practice Test

CPS Firefighter Test Practice Test

CPS Mechanical Aptitude Principles 5