Question:
Tension T is a force (N).
Linear density p is a mass
per length (kg/m).
Can you combine them
with exponents a.b so that
TV has units of velocity?
Question:
The picture below is a
standing wave on a string
with two xed ends. (Black
and red t
Phys 22: Homework 9 Solutions
HRK 25.34
The key piece of insight you need is that
Eint = 0
for a closed path in a pV diagram of a reversible process. The rst law of thermodynamics Eint =
Q + W then implies
Q = W
where Q is the heat (energy) that ows into
Phys 22: Homework 8 Solutions
HRK 24.6
24.6 (a)
First calculate the pressure in standard units
P=
1.1 107 cm Hg
(1.01 105 P a) = 1.46 104 P a
76 cm Hg
The number density n is given by
n
N
P
=
V
kT
1.46 104
(1.38 1023 )(295)
=
=
=
3.59 1016 molecules/m3
24
Phys 22: Homework 10 Solutions
HRK 26.7
Summarizing the information given in the question
WA
QIN
A
OU T
QA
=
=
=
5WB
3QIN
B
2QOU T
B
One way of doing this is as follows.
Use
eA
and
eB
|W A |
|QIN | | QOU T |
A
=A
|QIN |
|QIN |
A
A
=
=
|WB |
|QIN | | QOU T
Phys 22: Homework 5 Solutions
HRK 22.2
The thermometric property X that we are using is voltage, of which temperature is a linear function
(on this practical scale, not actual thermodynamic temperature) i.e.
T (X ) = aX + b
We are given two reference meas
Phys 22: Homework 4 Solutions
HRK 21.2
From the discussion of length contraction and time dilation we would expect the tube to appear
shorter (in the direction of motion) when we are moving at high speed with respect to it. The
proper length L0 is the len
Phys 22: Homework 3 Solutions
HRK 20.8
Denote the speed of the S waves as vs and the speed of the P waves as vp . The time taken to reach
the surface is ts for an S wave, and tp for a P wave. If the earthquake occurred d m below the
surface then
vs =
d
ts
Phys 22: Homework 1 Solutions
HRK 18.4
Since power is dened as dW we want to know how much work the pump is doing (Wpump ). We
dt
already know from the work-energy theorem that WT otal = K . In deriving Bernoullis equation
we saw there were two forces con
Phys 22: Homework 2 Solutions
HRK 19.2
The frequency, , is the number of full oscillations per second. Since the boat completes 12 oscillations in 30 seconds we have
12
= 0.4 Hz
30
=
If it takes 5s for a point (in this case, the crest) of the wave to trav
Phys 22: Homework 6 Solutions
HRK 23.10
Since
pV
= k,
NT
where N is the number of molecules. Since we have exactly one mole that means N = NA .
Rearranging,
V
kT
=
.
NA
p
This tells us the volume for each molecule.
23.10 (a)
V
NA
V
Vol per molecule:
NA
=
Phys 22: Homework 7 Solutions
HRK 24.5
First we need to nd the number of molecules per unit volume N/V , which is also called n (number
per volume instead of mass per volume like normal ).
24.5 (a)
N
V
N
V
N
n =
V
=
P
kB T
=
1.01 105
(1.38 1023 (273)
= 2.