Question 1

Which of the following best describes the density of a homogeneous material?

Accepted Answer

Density is the ratio of the material's mass to its volume and is constant throughout the material.

Question 2

A steel wrench and a steel nail have different masses and volumes. What can be said about their densities?

Accepted Answer

Both have the same density because they are made of the same material.

Question 3

What is the SI unit of pressure, and how is it defined?

Accepted Answer

The SI unit of pressure is the pascal, defined as $$1 \ \mathrm{Pa} = 1 \ \mathrm{N/m^2$}.$$

Question 4

Which equation correctly expresses the pressure at a depth $$h in a $$fluid of uniform density?

Accepted Answer

$$p = p_0$ + \rho g h$$

Question 5

A hydraulic lift uses Pascal's law to lift a car. If a force $$F_1 is $$applied to a piston of area $$A_1$$, what is the force $$F_2$$ exerted by a piston of area $$A_2 at $$the same height?

Accepted Answer

$$F_2$$ = $$F_1$$ \cdot ($$A_2$$ / $$A_1$$)$$

Question 6

A car tire is inflated to a gauge pressure of $$2.2 	imes 10^5$ Pa. If atmospheric pressure is 1.0$$ 	imes $$10^5 Pa$$, what is the absolute pressure inside the tire?

Accepted Answer

$$3.2 	imes 10^5$ Pa

Question 7

According to Archimedes's principle, what is the buoyant force on an object completely submerged in a fluid?

Accepted Answer

It is equal to the weight of the fluid displaced by the object.

Question 8

Which of the following best explains why a water strider can walk on water?

Accepted Answer

Surface tension allows the water surface to act like a membrane under tension.

Question 9

In steady flow, which of the following statements is true?

Accepted Answer

Every fluid element passing through a given point follows the same flow line.

Question 10

Which equation represents the continuity equation for an incompressible fluid?

Accepted Answer

$$A_1$$ $$v_1$$ = $$A_2$$ $$v_2$$

Question 11

Bernoulli's equation relates pressure, kinetic energy, and potential energy per unit volume in a fluid. Which of the following is the correct form?

Accepted Answer

$$p_1$$ + \rho g $$y_1$$ + \frac{1}{2} \rho $$v_1^2$$ = $$p_2$$ + \rho g $$y_2$$ + \frac{1}{2} \rho $$v_2^2$

Question 12

A giraffe's heart must generate high blood pressure to pump blood to its brain. According to Bernoulli's equation, why does the pressure drop as blood flows upward?

Accepted Answer

Because the blood's height increases, increasing gravitational potential energy.

Question 13

In a Venturi meter, why is the pressure lower at the throat (narrow section) than at the wider section?

Accepted Answer

Because the fluid speed is higher at the throat.

Question 14

Which of the following best describes laminar flow?

Accepted Answer

Adjacent layers of fluid slide smoothly past each other in a steady pattern.

Question 15

What happens to the viscosity of lava as its temperature increases?

Accepted Answer

Viscosity decreases.

Question 16

Why does turbulence in blood flow make noise that can be detected with a stethoscope?

Accepted Answer

Turbulent flow causes rapid, chaotic changes in velocity and pressure.

Question 17

A pipe narrows from a cross-sectional area of $$0.05 \ \mathrm{m^2$} to$$ $$0.01 \ \mathrm{m^2$}. If $$the speed of water in the wider section is $$2 \ \mathrm{m/s}$$, what is the speed in the narrow section?

Accepted Answer

$$10 \ \mathrm{m/s}$$

Question 18

Which of the following is NOT a consequence of surface tension?

Accepted Answer

The viscosity of water increasing.

Fluid Mechanics: Core Concepts and Applications

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