Question 1

A plastic block of dimensions 2.0 cm × 3.0 cm × 4.0 cm has a mass of 30. grams. What is its density?

Accepted Answer

A)  0.80 g/cm3 
B)  1.2 g/cm3 
C)  1.6 g/cm3 
D)  1.3 g/cm3 
E)  2.3 g/cm3 
A)  0.80 g/cm3 
B)  1.2 g/cm3 
C)  1.6 g/cm3 
D)  1.3 g/cm3 
E)  2.3 g/cm3

Question 2

An object will float in a fluid if the average density of the object is greater than the density of the fluid.

Accepted Answer

A) True 
 B)False

Question 3

A sphere of diameter 7.9 cm is completely submerged in water and seems to weigh 32.0% less in the water than out of it.
(a) What is the density of the sphere?
(b) If the sphere had been twice as dense, it would have weighed what % less in water than out?

Accepted Answer

(a) 3.13 ×

Question 4

As one stretches a metal rod, which condition is first reached?

Accepted Answer

A)  elastic limit 
B)  breaking point 
C)  fracture point 
D)  proportional limit 
A)  elastic limit 
B)  breaking point 
C)  fracture point 
D)  proportional limit

Question 5

A long telephone pole (wood density 0.80 kg/m3) is vertically lowered into a slightly larger vertical pipe which is filled with salt water of density 1.04 kg/m3. The pole ends up floating with what percent of the pole above the water?

Accepted Answer

23% above

Question 6

Irrotational flow means that a fluid element experiences a net angular velocity.

Accepted Answer

A) True 
 B)False

Question 7

Air is forced to flow over an object whose cross-section is shown in Figure 9-2.
 
The speed of the air flowing close to the top surface is ________ the speed of the air flowing close to the bottom surface.

Accepted Answer

A)  less than 
B)  greater than 
C)  equal to 
A)  less than 
B)  greater than 
C)  equal to

Question 8

Young's modulus is a(n)

Accepted Answer

A)  strain. 
B)  elastic modulus. 
C)  stress. 
D)  breaking strength. 
E)  pressure limit. 
A)  strain. 
B)  elastic modulus. 
C)  stress. 
D)  breaking strength. 
E)  pressure limit.

Question 9

A spherical inflated balloon is submerged in a pool of water. If it is further inflated so that its radius doubles, how is the buoyant force affected?

Accepted Answer

A)  8 times larger 
B)  not at all 
C)  4 times larger 
D)  2 times larger 
E)  6 times larger 
A)  8 times larger 
B)  not at all 
C)  4 times larger 
D)  2 times larger 
E)  6 times larger

Question 10

Strain is

Accepted Answer

A)  the stress per unit area. 
B)  the ratio of the change in length to the original length. 
C)  the ratio of stress to elastic modulus. 
D)  the applied force per unit area. 
A)  the stress per unit area. 
B)  the ratio of the change in length to the original length. 
C)  the ratio of stress to elastic modulus. 
D)  the applied force per unit area.

Question 11

Suppose that in an examination of a spinal injury it is found that the spinal fluid (with about the same density as water) will rise a vertical height of 13. cm in an open tube. What pressure does this correspond to, expressed in mm of mercury and in atmospheres?

Accepted Answer

9.6 mm Hg,

Question 12

An object is submerged in a swimming pool and of course the water exerts a buoyant force on the object. Suppose a thousand gallons of oil is spilled into the pool and now floats above the water. How is the buoyant force on the object changed by the overlying oil?

Accepted Answer

No change at all as long as th

Question 13

A container of water is placed on a scale, and the scale reads 120. g. Now a 20.0g piece of copper (specific gravity = 8.90) is suspended from a thread and lowered into the water, not touching the bottom of the container. What will the scale now read?

Accepted Answer

A)  140 g 
B)  122 g 
C)  138 g 
D)  112 g 
E)  120 g 
A)  140 g 
B)  122 g 
C)  138 g 
D)  112 g 
E)  120 g

Question 14

A mercury barometer

Accepted Answer

A)  is an open tube manometer. 
B)  is a closed tube manometer. 
C)  is usually 760. cm tall. 
D)  does not contain mercury. 
E)  measures gauge pressure. 
A)  is an open tube manometer. 
B)  is a closed tube manometer. 
C)  is usually 760. cm tall. 
D)  does not contain mercury. 
E)  measures gauge pressure.

Question 15

An incompressible fluid flows at 0.252 m/s through a 44. mm diameter (circular cross section) (a) section?
(b) what is the flow rate in liters/minute?

Accepted Answer

(a) 0.13 m

Question 16

An iron barge 25. m long and 4.0 m wide has a mass of 100,000.kg. What minimum depth of water is needed to float it?

Accepted Answer

The answer of An iron barge 25. m long and...

Question 17

Which of the following is NOT a unit of pressure?

Accepted Answer

A)  Pascal 
B)  psi 
C)  atmosphere 
D)  N.mS1U1P12S1S1P0 
E)  inches of mercury 
A)  Pascal 
B)  psi 
C)  atmosphere 
D)  N.mS1U1P12S1S1P0 
E)  inches of mercury

Question 18

When you are scuba diving, the pressure on your face plate

Accepted Answer

A)  is independent of both depth and orientation. 
B)  will be greatest when you are facing upward. 
C)  depends only on your depth, and not on how you are oriented. 
D)  will be greatest when you are facing downward. 
A)  is independent of both depth and orientation. 
B)  will be greatest when you are facing upward. 
C)  depends only on your depth, and not on how you are oriented. 
D)  will be greatest when you are facing downward.

Question 19

A piece of iron sinks to the bottom of a lake where the pressure is 21. atm. Which statement best describes what happens to the volume of that piece of iron?

Accepted Answer

A)  There has been no change in the volume of the iron. 
B)  Its volume decreases slightly. 
C)  Its volume increases slightly. 
D)  Its volume becomes 21. times greater. 
A)  There has been no change in the volume of the iron. 
B)  Its volume decreases slightly. 
C)  Its volume increases slightly. 
D)  Its volume becomes 21. times greater.

Question 20

All of the following are dimensionless except

Accepted Answer

A)  strain. 
B)  Reynolds number. 
C)  specific gravity. 
D)  bulk modulus. 
A)  strain. 
B)  Reynolds number. 
C)  specific gravity. 
D)  bulk modulus.

Exam 9: Solids and Fluids

A plastic block of dimensions 2.0 cm × 3.0 cm × 4.0 cm has a mass of 30. grams. What is its density?

An object will float in a fluid if the average density of the object is greater than the density of the fluid.

A sphere of diameter 7.9 cm is completely submerged in water and seems to weigh 32.0% less in the water than out of it. (a) What is the density of the sphere? (b) If the sphere had been twice as dense, it would have weighed what % less in water than out?

As one stretches a metal rod, which condition is first reached?

A long telephone pole (wood density 0.80 kg/m3) is vertically lowered into a slightly larger vertical pipe which is filled with salt water of density 1.04 kg/m3. The pole ends up floating with what percent of the pole above the water?

Irrotational flow means that a fluid element experiences a net angular velocity.

Air is forced to flow over an object whose cross-section is shown in Figure 9-2. The speed of the air flowing close to the top surface is ________ the speed of the air flowing close to the bottom surface.

Young's modulus is a(n)

A spherical inflated balloon is submerged in a pool of water. If it is further inflated so that its radius doubles, how is the buoyant force affected?

Strain is

Suppose that in an examination of a spinal injury it is found that the spinal fluid (with about the same density as water) will rise a vertical height of 13. cm in an open tube. What pressure does this correspond to, expressed in mm of mercury and in atmospheres?

An object is submerged in a swimming pool and of course the water exerts a buoyant force on the object. Suppose a thousand gallons of oil is spilled into the pool and now floats above the water. How is the buoyant force on the object changed by the overlying oil?

A container of water is placed on a scale, and the scale reads 120. g. Now a 20.0g piece of copper (specific gravity = 8.90) is suspended from a thread and lowered into the water, not touching the bottom of the container. What will the scale now read?

A mercury barometer

An incompressible fluid flows at 0.252 m/s through a 44. mm diameter (circular cross section) (a) section? (b) what is the flow rate in liters/minute?

An iron barge 25. m long and 4.0 m wide has a mass of 100,000.kg. What minimum depth of water is needed to float it?

Which of the following is NOT a unit of pressure?

When you are scuba diving, the pressure on your face plate

A piece of iron sinks to the bottom of a lake where the pressure is 21. atm. Which statement best describes what happens to the volume of that piece of iron?

All of the following are dimensionless except

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A long telephone pole (wood density 0.80 kg/m³) is vertically lowered into a slightly larger vertical pipe which is filled with salt water of density 1.04 kg/m³. The pole ends up floating with what percent of the pole above the water?