OAR OAR Mechanical Comprehension: Fluids Questions and Answers 3

Question 1

A tank is filled with water to a height of 5 meters. What is the approximate gauge pressure at the bottom of the tank? (Use g = 9.8 m/s²)

Accepted Answer

49,000 Pa

Answer

4,900 Pa

Answer

490 Pa

Answer

98,000 Pa

Question 2

Two identical ships are floating, one in freshwater and one in saltwater. Which ship sits lower in the water?

Accepted Answer

The ship in freshwater

Answer

The ship in saltwater

Answer

Both sit at the same level

Answer

It depends on the ship's speed

Question 3

If the flow rate through a pipe is 12 liters per minute and the cross-sectional area of the pipe is 4 cm², what is the flow velocity?

Accepted Answer

0.5 m/s

Answer

5 m/s

Answer

50 m/s

Answer

0.05 m/s

Question 4

A balloon filled with helium rises in air because of which principle?

Accepted Answer

Archimedes' principle — the buoyant force exceeds the balloon's weight

Answer

Bernoulli's principle — moving air creates lift

Answer

Pascal's principle — pressure distributes equally

Answer

Newton's third law — the air pushes the balloon up as a reaction

Question 5

In a U-tube manometer containing mercury, one side is connected to a pressurized gas line and the other is open to the atmosphere. If the mercury on the gas side is 15 cm lower than the open side, what does this indicate?

Accepted Answer

The gas pressure is above atmospheric pressure

Answer

The gas pressure is below atmospheric pressure

Answer

The gas pressure equals atmospheric pressure

Answer

The manometer is malfunctioning

Question 6

What is the primary reason that airplane wings generate lift, as related to fluid dynamics?

Accepted Answer

Air moves faster over the curved top surface, creating lower pressure above the wing

Answer

The wing pushes air downward and the reaction force lifts it

Answer

Air below the wing is compressed to a higher density

Answer

The wing creates a vacuum above it