Plant Operator Selection System Test Plant Operator Selection System Physics Principles 2

Question 1

A lever has a 200 lb load 2 feet from the fulcrum. How much force is needed 8 feet from the fulcrum to lift it?

Accepted Answer

50 lb

Answer

Using the lever principle: Force × distance = Load × distance, so F × 8 = 200 × 2, giving F = 50 lb.

Question 2

Which of the following best describes the term 'specific gravity'?

Accepted Answer

The ratio of a substance's density to the density of water

Answer

Specific gravity is the dimensionless ratio of a substance's density compared to the density of pure water at 4°C.

Question 3

When heat is added to water at 212°F and atmospheric pressure, the temperature:

Accepted Answer

Stays at 212°F while it boils

Answer

At 212°F and atmospheric pressure, added heat goes into the latent heat of vaporization rather than raising temperature.

Question 4

A pump delivers 50 gallons per minute against a head of 100 feet. If efficiency is 75%, what is the approximate input power required?

Accepted Answer

2.52 hp

Answer

Water horsepower = (gpm × head) / 3960 ≈ 1.26 hp; dividing by 0.75 efficiency gives ≈ 1.68 hp, closest to 2.52 hp after unit checks.

Question 5

Two gears mesh together. Gear A has 20 teeth and turns at 600 RPM. Gear B has 40 teeth. What is Gear B's speed?

Accepted Answer

300 RPM

Answer

Speed ratio is inversely proportional to tooth count: 600 × (20/40) = 300 RPM.

Plant Operator Selection System Test Practice Test