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AP Physics 2
Applications of Thermodynamics
1. from Knight, 12-25 0.0040 mol of gas undergoes
the process shown at right. What type of process
is this? What are the initial and final temperatures?
initial
final
2. from Knight, 12-26 0.0040 mol of gas follows the
hyperbolic trajectory shown at right. What type of
process is this? What are the initial and final
temperatures? What is the final volume?
initial
final
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3. from Knight, 12-27 A gas with an initial
temperature of 900C undergoes a process shown
to the right. What type of process is this? What
is the final temperature? How many moles of gas
are there?
final
initial
4. from Knight, 12-28 How much work is done
ON the gas in the process shown at right?
final
initial
5. from Knight, 12-31 A weather balloon rises through the atmosphere. Its volume expands
from 4.0 m3 to 12 m3 as the temperature drops from 20C to -10C. If the initial gas
pressure is 1.0 atm, what is the final pressure?
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6. from Giancoli, 15-10 Heat is allowed to flow
out of an ideal gas at a constant volume so that
its pressures drops from 2.2 atm to 1.4 atm.
Then, the gas expands at a constant pressure,
from a volume of 5.9 L to 9.3 L, where the
temperature reaches its original value.
a. Calculate the total work done by the gas
in the process.
b. Calculate the change in the internal energy of the gas.
c. Calculate the total heat flow into or out of the gas.
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7. from Etkina, 13-36 The following equations represent four parts (A, B, C, and D) of a cyclic
process with a gas. In this case, we consider the work done BY the system on the
environment, i.e., 𝑄 − 𝑊 = 𝑈𝑖𝑛𝑡𝑒𝑟𝑛𝑎𝑙
𝑊 = (3.0𝑥105
𝑁
𝑁
) (0.020 𝑚3 − 0.010 𝑚3 ) + 0 + (1.0𝑥105 2 ) (0.010 𝑚3 − 0.020 𝑚3 ) + 0
2
𝑚
𝑚
3
2
𝑈𝑖𝑛𝑡𝑒𝑟𝑛𝑎𝑙 = ( ) (1 𝑚𝑜𝑙) (8.3
𝐽
) [(700 𝐾 − 300 𝐾) + (480 𝐾 − 700 𝐾)
𝑚𝑜𝑙 𝐾
+ (240 𝐾 − 480 𝐾) + (360 𝐾 − 240𝐾)]
𝑄 = 𝑄𝐴 + 𝑄𝐵 +𝑄𝑐 + 𝑄𝐷
a. Draw and label a PV graph for the process. Include an appropriate scale.
b. Determine the net change in the internal energy during the entire cycle.
c. Determine the heating of the system for each of the four parts of the process.
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8. from Etkina, 13-26 A cyclic process involving
1 mole of ideal gas is shown at right.
a. Calculate the temperature at each
corner of the process.
A
B
D
C
b. Consider the part of the process AB
i. Determine the work done on the gas.1
ii. Determine the change in internal energy.
iii. Determine heat added to the gas.2
c. Consider the part of the process BC
i. Determine the work done on the gas.
ii. Determine the change in internal energy.
iii. Determine the heat added to the gas.
1
2
W+ = work done on the gas; W- = work done by the gas
Q+ = heat added to gas; Q- = heat released from gas
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d. Consider the part of the process CD
i. Determine the work done on the gas.
ii. Determine the change in internal energy.
iii. Determine the heat added to the gas.
e. Consider the part of the process DA.
i. Determine the work done on the gas.
ii. Determine the change in internal energy.
iii. Determine the heat added to the gas.
9. from Etkina, 13-25 A nuclear power plant operates between a high-temperature heat
reservoir at 560C and a low-temperature stream at 20C.
a. Determine the maximum efficiency of this thermodynamic engine.
b. Determine the heating rate (J/s) from the high-temperature heat reservoir to the
power plant so that it produces 1000 MW of power (work / time)
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10. From Giancoli, 15-26 A heat engine exhausts its heat at 340C and has an efficiency of 36%.
What exhaust temperature would enable it to achieve an efficiency of 42%?
11. From Giancoli, 15-27 A engine’s operating temperatures are 210C and 45C. The
engine’s power output is 910 W. Calculate the rate of heat output.
12. from Etkina, 13-28 A heat pump collects thermal energy from outside at 5C and delivers it
to the house at 40C.
a. Determine the maximum coefficient of performance.
b. If the motor uses 1000 J of electrical energy to do work during a certain time
interval, how much thermal energy is delivered to the house through heating?
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