Question 1

Which of the following best describes why the pressure at a given depth in a fluid is the same regardless of the shape of the container?

Accepted Answer

Because the pressure depends only on the height of the fluid column above the point, not the shape or volume of the container, as given by $$P = \rho g h.$$

Question 2

A hydraulic lift has a small piston of area $$0.01\,m^2$ and a large piston of area 1.0$$\,$$m^2. If a $$force of $$100\,N is $$applied to the small piston, what is the maximum weight that can be lifted by the large piston (neglecting friction)?

Accepted Answer

$$10,000\,N$$

Question 3

A block of wood with a density of $$0.70\,g/cm^3$ floats in water. What percentage of its volume is submerged?

Accepted Answer

70%

Question 4

Which of the following statements about atmospheric pressure is correct?

Accepted Answer

Atmospheric pressure decreases with increasing altitude because there is less air above you.

Question 5

A water tower is 30 m above a house. What is the water pressure at the house due to the tower? (Assume $$\rho = 1000\,kg/m^3$, g = 9.8$$\,$$m/s^2)$$

Accepted Answer

$$2.9 	imes 10^5$\,Pa$$

Question 6

Which of the following best explains why an airplane wing generates lift according to Bernoulli's principle?

Accepted Answer

The air moves faster over the top of the wing, creating lower pressure above the wing than below, resulting in an upward lift force.

Question 7

A cube of ice (density $$0.92\,g/cm^3$) floats in water. What fraction of the ice cube's volume is above the water surface?

Accepted Answer

8%

Question 8

A barometer reads 760 mm Hg at ground level. If you go up to a floor 8 m higher, what is the expected pressure difference? (Assume $$\rho_{air} = 1.3\,kg/m^3$, g = 9.8$$\,$$m/s^2)$$

Accepted Answer

$$\Delta P = \rho g h = (1.3)(9.8)(8) = 102\,Pa$$

Question 9

Which of the following is the correct SI unit for pressure, and how is it defined?

Accepted Answer

Pascal ($$Pa$$), defined as $$1\,N/m^2$

Question 10

A pipe carrying water narrows from a cross-sectional area of $$0.05\,m^2$ to 0.01$$\,$$m^2. If $$the speed of water in the wider section is $$2\,m/s$$, what is the speed in the narrower section? (Assume incompressible flow.)

Accepted Answer

$$10\,m/s$$

Question 11

A metal object weighs $$147\,N in $$air and $$127\,N$$ when fully submerged in water. What is the buoyant force acting on the object?

Accepted Answer

$$20\,N$$

Question 12

Which of the following is the correct expression for the mass flow rate $$\dot{m} in a $$pipe with cross-sectional area $$A$$, fluid density $$\rho$$, and velocity $$v$$?

Accepted Answer

$$\dot{m} = \rho A v$$

Question 13

A ping-pong ball is held in a vertical stream of air from a hair dryer and remains suspended. Which principle best explains this phenomenon?

Accepted Answer

Bernoulli's principle: the fast-moving air reduces pressure above the ball, balancing gravity.

Question 14

A submarine is submerged in seawater at a depth where the pressure is $$3.0 	imes 10^6$\,Pa. If $$the atmospheric pressure at the surface is $$1.0 	imes 10^5$\,Pa$$, what is the gauge pressure at this depth?

Accepted Answer

$$2.9 	imes 10^6$\,Pa$$

Question 15

Which of the following best describes the concept of specific gravity?

Accepted Answer

The ratio of the density of a substance to the density of water.

Question 16

A tank is filled with oil (density $$900\,kg/m^3$) to a depth of 5$$\,m$$. What is the pressure at the bottom of the tank due to the oil alone?

Accepted Answer

$$P = \rho g h = (900)(9.8)(5) = 44,100\,Pa$$

Question 17

A patient is connected to an IV bag that is $$1.5\,m$$ above the entry point into their arm. If the density of the IV fluid is $$1,050\,kg/m^3$, what is the pressure difference between the bag and the entry point? (g = 9.8$$\,$$m/s^2)$$

Accepted Answer

$$\Delta P = (1,050)(9.8)(1.5) = 15,435\,Pa$$

Question 18

Which of the following is NOT a fluid according to the five states of matter discussed?

Accepted Answer

Solid

Question 19

A river flows faster in a narrow section than in a wide section. Which equation best explains this observation?

Accepted Answer

Continuity equation: $$A_1$$ $$v_1$$ = $$A_2$$ $$v_2$$

Fluids: Properties, Pressure, and States of Matter

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