Chapter 14,15,16: Oscillations & Waves - Cabrillo College

Problem Set 11
Due: see website for due date
Chapter 14, 15, 16: Oscillations & Waves
Questions: 14.5, 14.20, 16.5, 16.11
Exercises & Problems: 14.6, 14.26, 14.41, 15.2, 15.25, 16.7, 16.11, 16.15
Q14.15: Sprinters push off from the ball off their foot, then bend their knee to bring their
foot up close to the body as they swing their leg forward for the next stride. Why is this
an effective strategy for running fast?
Q14.20: A person driving a truck on a "washboard" road, one with regularly spaced
bumps, notices an interesting effect: When the truck travels at low speed, the amplitude
of the vertical motion of the car is small. If the truck's speed is increased, the amplitude
of the vertical motion also increases, until it becomes quite unpleasant. But if the speed
is increased yet further the amplitude decreases, and at high speeds the amplitude of
the vertical motion is small again. Explain what is happening.
Q16.5: Certain illnesses inflame your vocal cords, causing them to swell. How does this
affect the pitch of your voice? Explain..
Q16.11: A friend's voice sounds different over the telephone than it does in person. This
is because telephones do not transmit frequencies over about 3000 Hz. 3000 Hz is well
above the normal frequency of speech, so why does eliminating these high frequencies
change the sound of a person's voice?
P14.6: An air-track glider attached to a spring oscillates between the 10 cm mark and
the 60 cm mark on the track. The glider completes 10 oscillations in 33 s. What are the
(a) period, (b) frequency, (c) amplitude, and (d) maximum speed of the glider?
P14.26: It is said that Galileo discovered a basic principle of the pendulum - that the
period is independent of the amplitude - by using his pulse to time the period of swinging
lamps in the cathedral as they swayed in the breeze. Suppose that one oscillation of a
swinging lamp takes 5.5 s. how long is the lamp chain?
P14.41: Vision is blurred if the head is vibrated at 29 Hz because the vibrations are
resonant with the natural frequency of the eyeball held by the musculature in its socket. If
the mass of the eyeball is 7.5 g, a typical value, what is the effective spring constant of the
musculature attached to the eyeball?
P15.2: The wave speed on a string under tension is 150 m/s when the tension is 75.0 N.
What tension will give a speed of 180 m/s?
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P15.25:
a. Telephone signals are often transmitted over long distances by microwaves. What is
the frequency of microwave radiation with a wavelength of 3.0 cm?
b. Microwave signals are beamed between two mountaintops 50 km apart. How long
does it take a signal to travel from one mountaintop to the other?
P16.7: A 2.0-m-long string is fixed at both ends and tightened until the wave speed is 40
m/s. What is the frequency of the standing wave shown in the figure?
P16.11:
a. What are the three longest wavelengths for standing waves on a 240-m-long string
that is fixed at both ends?
b. If the frequency of the second-longest wavelength is 50.0 Hz, what is the frequency
of the third-longest wavelength?
P16.15: The lowest note on a grand piano has a frequency of 27.5 Hz. The entire string
is 2.00 m long and has a mass of 400 g. The vibrating section of the string is 1.90 m
long. What tension is needed to tune this string properly?
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