Answers to the even-numbered assigned problems in Chapts 12, 14--16
The following is a list of the answers to the even-numbered assigned problems.
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Chapter 12
12-4
a) 1.2 m/s
b) 0.31 m
c) The amplitude becomes 0.15 m; but the wavelength, period, and wave speed are unchanged.
12-16
a) 3.00 m
b) 1.00 m
c) 0.750 m
12-18
a) 96.0 m/s
b) 461 N
12-44
a) 1/1000
b) -3.0 dB
12-54
a) 443 Hz
b) loosen
12-56
a) 375 Hz
b) 371 Hz
c) 4 Hz
12-68
a) 12.6 m
b) 1.26 km
Chapter 14
14-34
a) 20.8 min
b) 251 min
14-44 27.5° C
14-46 1.01 × 103 J/kg · K
14-54 105.5° C
14-64 4.54 × 103 W
14-76 21.4° C
Chapter 15
15-12
a) 3.74
b) This increase in volume of air in the lungs would be dangerous.
15-26 3800° C
15-52
a) 0
b) increased
c) increased by 534 J
d) Tb = 3Ta
15-56
a) 0.681 moles
b) 0.0333 m3
c) 2230 J done by the gas
d) 0
15-64
a) 0
b) -85.0 J
c) 1.12 × 103 K
15-76
a) 3.00 × 103 J into the gas
b) 2.00 × 103 J into the gas
c) Q is larger in part (a). ΔU is the same because the initial and final states are the same, but in (a) more work is done.
15-80
a) 8.0 × 105 Pa
b) Ta = 296 K, Tb = 1184 K, Tc = 296 K
c) ab: 6.00 × 104 J, heat entered the gas;
bc: -3.60 × 104 J, heat left the gas;
ca: -1.11 × 104 J, heat left the gas.
d) ab: 3.60 × 104 J, U increased;
bc: -3.60 × 104 J, U decreased;
ca: 0
Chapter 16
16-4
a) 2600 J
b) 29 %
16-30 +70 J/K; the entropy of the world increases
16-36 -6.31 J/K