Physics 2306
Spring 2007
First Exam
1) Which statement is true.
A sound wave is
A.
a transverse wave.
The displacement of air molecules and the pressure fluctuation
are in phase.
B.
a transverse wave.
The displacement of air molecules and the pressure fluctuation
are 90
°
out of phase.
C.
a transverse wave.
The displacement of air molecules and the pressure fluctuation
are 180
°
out of phase.
D.
a longitudinal wave.
The displacement of air molecules and the pressure
fluctuation are in phase.
E.
a longitudinal wave.
The displacement of air molecules and the pressure
fluctuation are 90
°
out of phase.
F.
a longitudinal wave.
The displacement of air molecules and the pressure
fluctuation are 180
°
out of phase.
25) The displacement of air molecules from equilibrium in a sound wave is given by
s(x,t) = (0.020 m)cos[(3.0 rad/meter)x
−
(500 rad/sec)t]
2) What is the amplitude (in meters) of the wave?
A.
3.0
B.
500
C.
2.1
D.
80
E.
0.013
F.
0.020
G.
9.4
H.
1,600
3) What is the period (in seconds) of the wave?
A.
3.0
B.
500
C.
2.1
D.
80
E.
0.013
F.
0.020
G.
9.4
H.
1,600
4) What is the wavelength (in meters) of the wave?
General expression for displacement of air molecules in a
sound wave:
s(x,t) = A cos[kx ±
ω
t]
Compare to the equation for the displacement of air
molecules given in this problem and identify the amplitude.
General expression for displacement of air molecules in a
sound wave:
s(x,t) = A cos[kx ±
ω
t]
Compare to the equation for the displacement of air
molecules given in this problem and identify
ω
= 500.
T = 1/f = 2
π
/
ω
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View Full DocumentA.
3.0
B.
500
C.
2.1
D.
80
E.
0.013
F.
0.020
G.
9.4
H.
1,600
5) What is the velocity of propagation (in meters/second) of the wave (positive wave
velocity is in the +xdirection and negative wave velocity is in the
−
xdirection)?
A.
170
B.
−
170
C.
27
D.
−
27
E.
1000
F.
−
1000
G.
520
H.
−
520
6) A pipe, which is 0.600 meters long, is open at both ends.
What is the frequency (in
Hertz) of the third harmonic from this pipe?
Assume the speed of sound is 344 m/s.
A.
573
B.
860
C.
1,150
D.
286
E.
143
F.
430
G.
387
H.
717
7 and 8) The displacement of a transverse wave is given by
y(x,t) = (0.020 m)cos[(3.0 rad/meter)x
−
(500 rad/sec)t]
7) What is the maximum transverse speed (in m/s ) of a point on the wave at the position
x = 1.0 meters?
A.
1,500
B.
170
C.
500
D.
0.060
E.
42
General expression for displacement of air molecules in a
sound wave:
s(x,t) = A cos[kx ±
ω
t]
Compare to the equation for the displacement of air
molecules given in this problem and identify k = 3.0.
λ
= 2
π
/k
General expression for displacement of air molecules in a
sound wave:
s(x,t) = A cos[kx ±
ω
t]
where
−
sign is a wave moving in the positive xdirection.
The speed of the wave is given by:
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 Fall '06
 YKim
 Physics, Electric charge, Fundamental physics concepts, D. E. F.

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