NAPT Fluid Mechanics and Hydraulics 3

Question 1

Hydrostatic pressure at a given depth depends on:

Accepted Answer

Only the fluid density and depth, not the container shape

Answer

Hydrostatic pressure P = ρgh depends only on fluid density and vertical depth, not on the shape of the container or the total volume of fluid — this is known as the hydrostatic paradox.

Question 2

The Venturi effect describes what happens when fluid flows through a constriction in a pipe:

Accepted Answer

Velocity increases and pressure decreases

Answer

The Venturi effect is a direct consequence of Bernoulli's principle and the continuity equation: as the cross-section narrows, velocity must increase and static pressure must correspondingly decrease.

Question 3

Hydraulic power (in watts) is calculated as:

Accepted Answer

Pressure × Volume Flow Rate

Answer

Hydraulic power P = Q × ΔP, where Q is the volume flow rate (m³/s) and ΔP is the pressure difference (Pa); this gives power in watts (W = J/s).

Question 4

A U-tube manometer is used to measure:

Accepted Answer

Pressure differences between two points

Answer

A U-tube manometer measures pressure difference by comparing the height of fluid columns in two connected arms; the height difference directly corresponds to the pressure difference.

Question 5

Surface tension in a liquid is caused by:

Accepted Answer

Cohesive forces between liquid molecules at the surface

Answer

Surface tension arises because molecules at the surface have fewer neighbors to bond with than interior molecules, creating a net inward cohesive force that makes the surface behave like a stretched membrane.

NAPT - Navy Advanced Programs Test Practice Test

NAPT - Navy Advanced Programs Test Practice Test

NAPT Fluid Mechanics and Hydraulics 3