Thermodynamics and FluidsReview

Multiple Choice• Answer the five multiple choice

questions with your group• Give a confidence rating to each

question– 5 indicates that you are most confident– 1 indicates that you are least confident

• Your confidence rating determines the number of points you will receive for a correct answer

1. A fluid flows steadily from left to right in the pipe shown above. The diameter of the pipe is less at point 2 than at point 1, and the fluid density is constant throughout the pipe. How do the velocity of flow and the pressure at points 1 and 2 compare?

a. v1 < v2 P1 = P2

b. v1 < v2 P1 > P2

c. v1 = v2 P1 < P2

d. v1 > v2 P1 = P2

e. v1 > v2 P1 > P2

2. Each of the beakers above is filled to the same depth h with a liquid of density ρ. The area A of the flat bottom is the same for each beaker. Which of the following ranks the beakers according to the net downward force exerted by the liquid on the flat bottom, from greatest force to least force.a. I, III, II, IVb. I, IV, III, IIc. II, III, IV, Id. IV, III, I, IIe. None of the above; the force on each is the same.

3. A spring scale calibrate in kg is used to determine the density of a rock specimen. The reading on the spring scale is 0.45 kg when the specimen is suspended in air and 0.36 kg when the specimen is fully submerged in water. If the density of water is 1000 kg/m3, the density of the rock specimen is…

a. 2.0 × 102 kg/m3 b. 8.0 × 102 kg/m3

c. 1.25 × 103 kg/m3

d. 4.0 × 103 kg/m3

e. 5.0 × 103 kg/m3

A certain quantity of an ideal gas initially at temperature T0, pressure p0, and volume V0 is compressed to one half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).

4. Which of the following is true of the mechanical work done on the gas?

a. It is greatest for process 1.b. It is greatest for process 3.c. It is the same from processes 1 and 2 and less for process 3.d. It is the same for processes 2 and 3 and less for process 1.e. It is the same for all three processes.

A certain quantity of an ideal gas initially at temperature T0, pressure p0, and volume V0 is compressed to one half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).

5. Which of the following is true of the final temperature of this gas?

a. It is greatest for process 1.b. It is greatest for process 2.c. It is greatest for process 3.d. It is the same for processes 1 and 2.e. It is the same for processes 1 and 3.

Round 2

1. A monatomic ideal gas undergoes an adiabatic expansion. During this process, the temperature of the gas…

a. Remains constantb. Increases.c. Decreases.d. Increases, then decreases.e. Decreases, then increases.

2. Two samples of a monatomic ideal gas are being kept at the same temperature and pressure in different containers. Container A has twice the volume of container B. What can you say about the internal energy of container A compared to container B?

a. The internal energy of both containers is identical.b. The internal energy of container A is half the internal

energy of container B.c. The internal energy of container A is twice the internal

energy of container B.d. The internal energy of container A is more than twice

the internal energy of container B.e. The internal energy of container A is less than half the

internal energy of container B.

3. A metal bar has a coefficient of linear expansion of 5 × 10-6 (ºC)-1. If the bar is originally 1.0 m long at 20ºC, how much longer would is it at 120ºC?

a. 1.0005 mb. 19 × 10-4 mc. 5 × 10-6 md. 0.5 mme. 2.0 mm

4. A sample of 10 moles of an ideal gas is originally at a pressure of 300 kPa. It undergoes an isothermal compression from an original volume of 1.2 m3 to a final volume of 0.4 m3. The final pressure is most nearly…

a. 100 kPab. 600 kPac. 90 kPad. 9000 kPae. 900 kPa

5. Through a series of thermodynamic processes, the internal energy of a sample of confined gas is increased by 560 J. If the net amount of work done on the sample by its surroundings is 320 J, how much heat was transferred between the gas and its environment?

a. 240 J absorbedb. 240 J dissipatedc. 880 J absorbedd. 880 J dissipatede. None of the above