Mechanical Aptitude Mechanical Aptitude Fluid Dynamics Principles 4

Question 1

Two pipes of equal length carry the same fluid at the same pressure difference. Pipe A has a diameter of 1 inch and Pipe B has a diameter of 2 inches. Which carries more flow?

Accepted Answer

Pipe B carries more flow

Answer

By the Hagen-Poiseuille equation, flow rate is proportional to the fourth power of radius, so doubling diameter increases flow by a factor of 16.

Question 2

What does the Reynolds number indicate about fluid flow?

Accepted Answer

Whether flow is laminar or turbulent

Answer

The Reynolds number predicts flow regime: below ~2,300 is laminar, above ~4,000 is fully turbulent, and in between is transitional.

Question 3

A ship floats because it displaces a volume of water whose weight equals the ship's total weight. This is a direct application of:

Accepted Answer

Archimedes' principle

Answer

Archimedes' principle states that a floating object displaces fluid equal in weight to the object's own weight.

Question 4

In a fluid system, a manometer is used to measure:

Accepted Answer

Pressure differences

Answer

A manometer measures pressure by comparing fluid column heights, giving direct readings of pressure or pressure differences.

Question 5

When selecting a centrifugal pump for a system, what does the 'head' rating refer to?

Accepted Answer

The energy added to the fluid per unit weight, expressed as a height

Answer

Pump head is the energy per unit weight of fluid, equivalent to the height the pump could raise the fluid against gravity.

Mechanical Aptitude Test Practice Test

Mechanical Aptitude Test Practice Test

Mechanical Aptitude Mechanical Aptitude Fluid Dynamics Principles 4