CPS Mechanical Aptitude Principles 3

Question 1

A 100-lb load rests on a board pivoting on a fulcrum. The load is 2 ft from the fulcrum and the effort arm is 8 ft. How much effort is needed to balance it?

Accepted Answer

25 lb

Answer

Effort × effort arm = load × load arm: 100 × 2 = E × 8, so E = 25 lb.

Question 2

A block-and-tackle system has 4 supporting rope sections lifting a load. What is its ideal mechanical advantage?

Accepted Answer

4

Answer

Mechanical advantage of a pulley system equals the number of rope sections supporting the load.

Question 3

A longer ramp used to raise a barrel to the same height requires what change in pushing force?

Accepted Answer

Less force over a longer distance

Answer

A longer inclined plane reduces the force needed but increases the distance traveled.

Question 4

Which of these is an example of a third-class lever?

Accepted Answer

A pair of tweezers

Answer

Tweezers apply effort between the fulcrum and load, defining a third-class lever.

Question 5

Two gears mesh, and an idler gear is placed between the driver and driven gears. What is the idler gear's main effect?

Accepted Answer

It reverses the driven gear's direction without changing the speed ratio

Answer

An idler gear changes rotation direction but does not alter the overall speed ratio between driver and driven.

CPS Firefighter Test Practice Test

CPS Firefighter Test Practice Test

CPS Mechanical Aptitude Principles 3