OAR OAR Mechanical Comprehension: Fluids 5

Question 1

A ship displaces 500 tons of seawater. According to Archimedes' principle, the ship's weight is:

Accepted Answer

Exactly 500 tons

Answer

Less than 500 tons

Answer

More than 500 tons

Answer

Cannot be determined without knowing volume

Question 2

In a venturi meter, the pressure is measured at the wide inlet and the narrow throat. The flow rate is determined from the:

Accepted Answer

Pressure difference between inlet and throat

Answer

Sum of the two pressures

Answer

Temperature difference between the sections

Answer

Pipe material and diameter only

Question 3

Which of the following increases the viscosity of most liquids?

Accepted Answer

Decreasing temperature

Answer

Increasing temperature

Answer

Increasing flow velocity

Answer

Reducing pipe diameter

Question 4

A hydraulic cylinder with a 3-inch diameter piston must lift 1,000 lbs. What minimum pressure is needed? (Area = πr²)

Accepted Answer

About 212 psi

Answer

About 53 psi

Answer

About 71 psi

Answer

About 141 psi

Question 5

Laminar flow in a pipe is most likely when:

Accepted Answer

The fluid is highly viscous and velocity is low

Answer

Flow velocity is very high and pipe diameter is large

Answer

The pipe has many bends and rough walls

Answer

The fluid is a gas, not a liquid

Question 6

Water hammer in a piping system is caused by:

Accepted Answer

Sudden stoppage or reversal of fluid flow creating a pressure shock wave

Answer

Pipe vibration from external machinery

Answer

Overheating of fluid beyond boiling point

Answer

Excessive filter blockage reducing flow

Question 7

If the specific gravity of mercury is 13.6, how high a column of mercury corresponds to 14.7 psi (one atmosphere)?

Accepted Answer

About 30 inches

Answer

About 10 inches

Answer

About 76 inches

Answer

About 136 inches