Chapter 10: Fluids

Question 1

At a fixed depth within a fluid at rest, the pressure pushing upward is _______

Answer 1

equal to the pressure pushing downward

Question 2

While swimming near the bottom of a pool, you let out a small bubble of air. As the bubble rises toward the surface, what happens to its diameter?

Answer 2

Its diameter increases slightly

Question 3

What is the difference between the pressures inside and outside a tire called?

Answer 3

gauge pressure

Question 4

The three common phases of matter are _________

Answer 4

solid, liquid, and gas.

Question 5

Density is _________

Answer 5

proportional to mass and inversely proportional to volume.

Question 6

Substance A has a density of 3.0 g/cm3 and substance B has a density of 4.0 g/cm3. In order to obtain equal masses of these two substances, the ratio of the volume of A to the volume of B will be equal to

Answer 6

4:3

Question 7

Which of the following is not a unit of pressure?

Answer 7

N/m

Question 8

Consider three drinking glasses. All three have the same area base, and all three are filled to the same depth with water. Glass A is cylindrical. Glass B is wider at the top than at the bottom, and so holds more water than A. Glass C is narrower at the top than at the bottom, and so holds less water than A. Which glass has the greatest liquid pressure at the bottom?

Answer 8

All three have equal pressure

Question 9

50 cm3 of wood is floating on water, and 50 cm3 of iron is totally submerged. Which has the greater buoyant force on it?

Answer 9

the iron

Question 10

Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?

Answer 10

buoyant force is the same in both

Question 11

An ideal fluid flows at 12 m/s in a horizontal pipe. If the pipe widens to twice its original radius, what is the flow speed in the wider section?

Answer 11

3.0 m/s

Question 12

A sky diver falls through the air at terminal velocity. The force of air resistance on him is _________

Answer 12

equal to his weight

Question 13

A plastic block of dimensions 2.00 cm x 3.00 cm x 4.00 cm has a mass of 30.0 g. What is its density?

Answer 13

1.25 g/cm^3

Question 14

A liquid has a specific gravity of 0.357. What is its density?

Answer 14

357 kg/m^3

Question 15

A person weighing 900 N is standing on snowshoes. Each snowshoe has area 2500 cm2. What is the pressure on the snow?

Answer 15

1800 N/m^2

Question 16

How much pressure (absolute) must a submarine withstand at a depth of 120.0 m in the ocean?

Answer 16

1310 kPa

Question 17

A 1.0-m3 object floats in water with 20% of it above the waterline. What does the object weigh out of the water?

Answer 17

7840 N

Question 18

A solid object floats in water with three-fourths of its volume beneath the surface. What is the object’s density?

Answer 18

750 kg/m^3

Question 19

Liquid flows through a 4.0 cm diameter pipe at 1.0 m/s. There is a 2.0 cm diameter restriction in the line. What is the velocity in this restriction?

Answer 19

4.0 m/s

Question 20

A 500-N weight sits on the small piston of a hydraulic machine. The small piston has an area of 2.0 cm2. If the large piston has an area of 40 cm2, how much weight can the large piston support?

Answer 20

10000 N

Question 21

A block of metal weighs 40 N in air and 30 N in water. What is the buoyant force of the water?

Answer 21

10 N

Question 22

If the density of gold is 19.3 x 10^3 kg/m3, what buoyant force does a 0.60-kg gold crown experience when it is immersed in water?

Answer 22

0. 30 N

Question 23

A steel ball sinks in water but floats in a pool of mercury. Where is the buoyant force on the ball greater?

Answer 23

floating on the mercury

Question 24

As the speed of a moving fluid increases, the pressure in the fluid __________

Answer 24

decreases

Question 25

Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the water pressure greatest?

Answer 25

point B

Question 26

When you blow some air above a paper strip, the paper rises. This is because ________

Answer 26

the air above the paper moves faster and the pressure is lower

Question 27

You are walking out on frozen Lake Bemidji during winter and you begin to hear the ice cracking beneath you. What is your best strategy for getting off the ice safely?

Answer 27

Lie down flat on the ice and crawl toward shoree

because pressure is decreased on the ice

Question 28

Three containers are filled with water to the same height and have the same surface area at the base, but the total weight of water is different for each. Which container has the greatest total force acting on its base?

Answer 28

All three are equal

Question 29

Thermometers often use mercury or alcohol in a thin glass tube, but barometers never use alcohol. Why?

Answer 29

mercury is denser than alcohol

Question 30

When you drink liquid through a straw, which of the items listed below is primarily responsible for how the straw works?

Answer 30

atmospheric pressure

Question 31

Answer 31

Question 32

Answer 32

Question 33

Answer 33

Question 34

Answer 34

Both require the same force, difference in pressure between the top and bottom of both bricks is the same

Question 35

Answer 35

Question 36

A boat carrying a large chunk of lead is floating on a small pond. The chunk is then thrown overboard and sinks. What happens to the water level in the pond (with respect to the shore)?

Answer 36

It lowers

Question 37

Answer 37

Question 38

Answer 38

Blood pressure would be higher

Question 39

Answer 39

Question 40

Answer 40

Question 41

Answer 41

Question 42

Answer 42

smoke rises more rapidly in the chimney