Plant Operator Selection System Test Plant Operator Selection System Physics Principles 3

Question 1

A fixed pulley system with one movable pulley supports a 300 lb load. Approximately how much effort force is required (ignoring friction)?

Accepted Answer

150 lb

Answer

A single movable pulley gives a mechanical advantage of 2, so effort = 300 ÷ 2 = 150 lb.

Question 2

Which law states that the volume of a gas is inversely proportional to its pressure at constant temperature?

Accepted Answer

Boyle's Law

Answer

Boyle's Law states P₁V₁ = P₂V₂ at constant temperature, meaning volume decreases as pressure increases.

Question 3

A steam pipe carries steam at 150 psi gauge pressure. What is the approximate absolute pressure?

Accepted Answer

164.7 psia

Answer

Absolute pressure = gauge pressure + atmospheric pressure (14.7 psia), so 150 + 14.7 = 164.7 psia.

Question 4

If a 10-ohm and a 20-ohm resistor are connected in parallel, what is the combined resistance?

Accepted Answer

6.67 ohms

Answer

1/R = 1/10 + 1/20 = 3/20, so R = 20/3 ≈ 6.67 ohms.

Question 5

An object is moving at 30 ft/s. If it decelerates uniformly and stops in 5 seconds, what is the deceleration?

Accepted Answer

6 ft/s²

Answer

Deceleration = change in velocity ÷ time = 30 ft/s ÷ 5 s = 6 ft/s².

Plant Operator Selection System Test Practice Test