OAR OAR Mechanical Comprehension: Fluids 4

Question 1

Which of the following is an example of a non-Newtonian fluid?

Accepted Answer

Ketchup

Answer

Water

Answer

Air

Answer

Gasoline

Question 2

A pipe carrying water branches into two equal pipes. If the flow rate in the main pipe is 8 gal/min, what is the flow rate in each branch?

Accepted Answer

4 gal/min

Answer

8 gal/min

Answer

16 gal/min

Answer

2 gal/min

Question 3

What is cavitation in a fluid system?

Accepted Answer

Buildup of air bubbles at the pump inlet that collapse when pressure rises, causing damage

Answer

Gradual corrosion of pipe walls by acidic fluids

Answer

Separation of oil and water in a mixed fluid

Answer

Increase in fluid density under high pressure

Question 4

A hydraulic system transmits 2,000 lbs of force through fluid. If there are no losses, the work done by the input piston equals the work done by the output piston because:

Accepted Answer

Energy is conserved — force × distance is equal on both sides

Answer

Hydraulic fluid stores energy

Answer

The fluid multiplies energy

Answer

Larger pistons always move farther

Question 5

Which condition must be true for Bernoulli's equation to apply without correction?

Accepted Answer

The flow must be steady and the fluid ideal (inviscid, incompressible)

Answer

The fluid must be compressible

Answer

The fluid must be viscous

Answer

The pipe must be vertical

Question 6

A fluid exerts a force on a curved pipe bend. In which direction is the net resultant force on the bend if flow turns 90°?

Accepted Answer

Diagonally, combining both the inlet and outlet momentum directions

Answer

Along the original flow direction only

Answer

Along the exit flow direction only

Answer

There is no net force on a smooth bend

Question 7

Atmospheric pressure at sea level is approximately 14.7 psi. What is the absolute pressure at the bottom of a pool that creates 5 psi of gauge pressure?

Accepted Answer

19.7 psi

Answer

5 psi

Answer

9.7 psi

Answer

14.7 psi