Q: Which of the following is a correct unit conversion for pressure?

$$1\ \mathrm{atm} = 1.013 \times 10^5$\ \mathrm{Pa}$$

Question 1

Which of the following best describes the difference between laminar and turbulent flow in a fluid moving through a tube?

Accepted Answer

Laminar flow has a parabolic velocity profile with smooth, parallel layers, while turbulent flow is chaotic and irregular.

Question 2

A fluid with density $$\rho = 1000\ \mathrm{kg/m^3$}$$ flows through a tube with cross-sectional area $$A = 0.01\ \mathrm{m^2$} at a $$velocity $$v = 2\ \mathrm{m/s}. $$What is the volume flow rate $$Q$$?

Accepted Answer

$$Q = 0.02\ \mathrm{m^3$/s}$$

Question 3

The Reynolds number $$Re is $$used to predict the type of flow in a tube. Which formula correctly expresses $$Re$$ for a fluid?

Accepted Answer

$$Re = \dfrac{\rho v d}{\eta}$$

Question 4

A nurse uses a hypodermic syringe with a narrow needle to inject medicine. According to the equation of continuity, what happens to the velocity of the fluid as it passes from the wide barrel into the narrow needle?

Accepted Answer

The velocity increases as the area decreases.

Question 5

Which of the following is the correct expression for hydrostatic pressure at a depth $$h in a $$liquid of density $$\rho$$, with atmospheric pressure $$p_0$$ acting on the surface?

Accepted Answer

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

Question 6

A water tank is open to the atmosphere and has a small hole at the bottom. Using Torricelli’s law, what is the speed $$v of $$water exiting the hole if the water level above the hole is $$h$$?

Accepted Answer

$$v = \sqrt{2gh}$$

Question 7

A pipe carrying water narrows from a diameter of $$0.10\ \mathrm{m} to$$ $$0.05\ \mathrm{m}. If $$the velocity in the wider section is $$1.0\ \mathrm{m/s}$$, what is the velocity in the narrower section? (Assume incompressible flow.)

Accepted Answer

$$v_2 = 4.0$$\ \mathrm{m/s}$$

Question 8

Which of the following statements about Bernoulli’s equation is correct?

Accepted Answer

Bernoulli’s equation relates pressure, kinetic energy per unit volume, and potential energy per unit volume along a streamline.

Question 9

A horizontal pipe carries water at two points: point 1 with area $$A_1$$ and velocity $$v_1$$, and point 2 with area $$A_2$$ and velocity $$v_2. If$$ $$A_1 = 2A_2$, what is the ratio v_2$/v_1$?

Accepted Answer

$$v_2$$/$$v_1 = 2$

Question 10

A fluid flows through a horizontal tube. At point 1, the pressure is $$p_1$$ and the velocity is $$v_1. At $$point 2, the pressure is $$p_2$$ and the velocity is $$v_2. $$According to Bernoulli’s equation, if $$v_2$$ \u003e $$v_1$$, what can be said about $$p_2$$ compared to $$p_1$$?

Accepted Answer

$$p_2$$ \u003c $$p_1$$

Question 11

A large open reservoir is connected to a small spigot at the bottom. If the atmospheric pressure is $$p_0$$ and the water level above the spigot is $$h$$, what is the pressure just inside the spigot?

Accepted Answer

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

Question 12

Which of the following is a correct unit conversion for pressure?

Accepted Answer

$$1\ \mathrm{atm} = 1.013 	imes 10^5$\ \mathrm{Pa}$$

Question 13

A fluid with dynamic viscosity $$\eta$$ flows through a tube of diameter $$d at $$average velocity $$v. If $$the density is $$\rho$$, which change will most likely cause the flow to become turbulent?

Accepted Answer

Increasing the velocity $$v$$

Question 14

A water pistol has a barrel of area $$A_1$$ and a nozzle of area $$A_2$$ ($$A_2$$ \u003c $$A_1). If $$the velocity in the barrel is $$v_1$$, what is the velocity in the nozzle $$v_2$$?

Accepted Answer

$$v_2$$ = \dfrac{$$A_1$$}{$$A_2$$} $$v_1$$

Question 15

A fluid flows upward through a vertical pipe. At the bottom, the pressure is $$p_1$$ and the height is $$h_1. At $$the top, the pressure is $$p_2$$ and the height is $$h_2. $$According to Bernoulli’s equation, which term accounts for the change in gravitational potential energy?

Accepted Answer

$$\rho g (h_2$ - h_1$)$$

Question 16

A patient receives an IV drip. If the bag is raised higher above the patient, what happens to the pressure at the needle tip?

Accepted Answer

The pressure increases due to greater $$h in$$ $$p = p_0$ + \rho g h$$

Question 17

A river flows with average velocity $$v$$ and cross-sectional area $$A. If $$the river narrows and the area decreases to $$A/2$$, what happens to the velocity, assuming incompressible flow?

Accepted Answer

The velocity doubles.

Question 18

Which of the following is NOT a factor in the calculation of Reynolds number for flow in a tube?

Accepted Answer

Gravitational acceleration $$g$$

Question 19

A fire hose has a diameter of $$0.08\ \mathrm{m}$$ and ejects water at a velocity of $$15\ \mathrm{m/s}. $$What is the volume flow rate $$Q$$?

Accepted Answer

$$Q = 0.075\ \mathrm{m^3$/s}$$

Fluid Dynamics: Core Concepts and Applications

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