Excursions in Physics
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Third Hour Exam
October 27, 2000

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For every question, also consider as a possible answer
E) none of the above

Possibly useful information:

v = x / t
p = m v
T = 2 Ø
a = v / t
PEg = m g h
T = 2 Ø
v = vi + a t
PEspg = (1/2) k x2
v =
x = xi + vi t + (1/2) a t2
KE = (1/2) m v2

v = (wavelength) x (frequency)
y = yi + vyi t + (1/2) ay t2
F = k x
L = (n) x (half wavelength)
v = r w
E = KE + PE
F = m a
Ei = Ef
F12 = - F21
pi = pf
w = mg

Fc = m v2 / r
g = 9.8 m/s2 10 m/s2

F = p / t

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For every question, also consider as a possible answer
E) none of the above

1. Increasing the mass of a simple pendulum harmonic oscillator makes its period
A) longer
B) shorter
C) unchanged

2. Increasing the spring constant k (that is, using a stronger spring) in a mass-and-spring simple harmonic oscillator makes its period
A) longer
B) shorter
C) unchanged

3. Increasing the mass m of a mass-and-spring simple harmonic oscillator makes its period
A) longer
B) shorter
C) unchanged
 
4. A mass-and-spring simple harmonic oscillator has maximum kinetic energy
A) at its equilibrium position
B) when its displacement equals its amplitude
C) half way between equilibrium and amplitude
D) three-fourths of the way between equilibrium and amplitude
 
5. A mass-and spring simple harmonic oscillator has maximum potential energy at
A) its equilibrium position
B) when its displacement equals its amplitude
C) half way between equilibrium and amplitude
D) three-fourths of the way between equilibrium and amplitude
 
6. The period of a simple harmonic oscillator is
A) the time required for one oscillation
B) the number of oscillations per second
C) the energy stored in the oscillations
D) the maximum distance moved from equilibrium
 
7. The frequency of a certain oscillator is 100 Hz; its period is
A) 0.1 s
B) 0.01 s
C) 0.001 s
D) 0.0001 s
 
8. There are "signals" of many different frequencies coming into the antenna of your radio. Only the one with a particular frequency is amplified and produces the sound you listen to. This is an example of
A) resonance
B) damping
C) timbre or quality
D) fundamental regeneration


9. Which of the following is a longitudinal wave?
A) light
B) wave on a string
C) sound
D) all of the above
 
10. A wave has a frequency of 50 Hz and a wavelength of 0.5 m. It has a wave speed of
A) 2.5 m/s
B) 10 m/s
C) 25 m/s
D) 100 m/s
 
11. A wave has a frequency of 32 Hz and travels 4 m in one second. It has
A) a wave speed of 128 m/s and a wavelength of 8 m.
B) a wave speed of 128 m/s and a wavelength of 1/8 m.
C) a wave speed of 4 m/s and a wavelength of 1/8 m
D) a wave speed of 4 m/s and a wavelength of 8 m
 
12. A wave has a frequency of 25 Hz and travels 5 m in one second. It has
A) a wave speed of 100 m/s and a wavelength of 5 m.
B) a wave speed of 100 m/s and a wavelength of 1/5 m.
C) a wave speed of 5 m/s and a wavelength of 1/5 m
D) a wave speed of 5 m/s and a wavelength of 5 m
 
13. For standing waves on a string,
A) a node is located at each end
B) a whole number times half the wavelength equals the length of the string
C) the whole "pattern" of standing waves occurs only for certain frequencies
D) all of the above
 
14. For standing waves on a string, the distance between adjacent nodes is always
A) the length of the string
B) one wavelength
C) one half the wavelength
D) half the length of the string
 
15. For standing waves on a string, the distance between adjacent antinodes is always
A) half the length of the string
B) one half the wavelength
C) one wavelength
D) the length of the string
 
16. A bobber on a fishing line oscillates up and down two (2) times per second as waves pass by. The waves have a wavelength of 25 cm. The waves are traveling at
A) 12.5 cm/s
B) 25 cm/s
C) 50 cm/s
D) 100 cm/s


17. If you put your fingertip in a pool of water and repeatedly move it up and down, you will create circular water waves that move out from that point. What will happen to the wavelength of these waves if you move your finger up and down more slowly (or less frequently)?
A) increase
B) remain the same
C) decrease
 
18. Sound is
A) an electromagnetic wave
B) a polarized wave
C) a longitudinal wave
D) all of the above

19. " Infrasonic" means
A) lower than the range of human hearing
B) higher than the range of human hearing
C) faster than the speed of sound
D) slower than the speed of sound
 
20. Bats and dolphins use echolocation to navigate or the find food or to find their way without relying on sight. The frequencies they use are
A) supersonic
B) infrasonic
C) ultrasonic
D) microsonic

21. The range of human hearing is about
A) 10 Hz to 100 Hz
B) 50 Hz to 500 Hz
C) 50 Hz to 20 kHz
D) 1 kHz to 100 kHz
 
22. Ella Fitzgerald made commercials for Memorex in which she used her voice to break a wine glass. This is an example of
A) echolocation
B) supersonic sound
C) ultrasonic frequencies
D) resonance
 
23. Beats are heard when two sounds have
A) nearly the same amplitude
B) nearly the same frequencies
C) twice the amplitude
D) exactly twice the frequency
 
24. The fundamental frequency present in a sound is the
A) sum of all the frequencies mixed together
B) difference between the highest and lowest frequencies present
C) lowest frequency present
D) highest frequency present

25. The fundamental frequency present in a sound determines the
A) quality or timbre
B) amplitude or loudness
C) pitch or note
D) all of the above
 
26. The "pitch" of a sound is determined by its
A) overtones frequencies
B) harmonics frequencies
C) fundamental frequency
D) resonance frequency
 
27. The quality or timbre -- the distincitive characteristic -- of a sound is determined by its
A) overtones or harmonics
B) amplitude or loudness
C) attack or decay
D) fundamental frequency
 
28. Consider a musical note of 262 hertz (middle “C”). Two octaves higher is represented by a musical note of
A) 131 Hz
B) 524 Hz
C) 1048 Hz
D) 1572 Hz
 
29. Suppose you play a note of a certain pitch on a violin. You can produce a higher-pitched note by
A) shortening the length of the string that is allowed to vibrate
B) decreasing the tension of the string (loosening the string)
C) increasing the linear mass density of the string (using a "heavier" string)
D) lengthening the part of the string that vibrates.
 
30. When a flute sound is viewed on an oscilloscope, the sound wave is very smooth. This is because
A) the amplitude is always small (flutes are quiet)
B) it has practically no overtones or harmonics
C) its fundamental frequency has a smaller amplitude than its second and third harmonics
D) its harmonics get larger and larger
 
31. When a trumpet sound is viewed on an oscilloscope, the sound wave is very complex. This is because
A) the amplitude is always large (trumpets are loud)
B) it has practically no overtones or harmonics
C) it has many overtones or harmonics
D) its has only even-numbered overtones or harmonics

32. A petroleum geologist might use a very carefully calibrated simple pendulum to do “prospecting” for a large pool of oil. If this “prospector” were over such a large pool of oil, she or he would find the period of this simple pendulum to be
A) longer
B) shorter
C) unchanged
than normal.

33. Increasing the length of a simple pendulum makes its period
A) longer
B) shorter
C) unchanged

34. The period of a simple pendulum depends upon its
A) mass
B) amplitude
C) length

35. Ordinary household electricity is alternating current with a frequency of 60 Hz. Its period is
A) 60 cycles per second.
B) 120 cycles per second.
C) 0.0333 s.
D) 0.0167 s.

36. If you apply a force to an oscillator at its natural frequency, you will produce motion
A) at exactly twice that frequency
B) at exactly one-half that frequency
C) with an amplitude that dies out or gets smaller.
D) with large amplitude

37. As the amplitude of a simple harmonic oscillator increases, its frequency
A) increases
B) stays the same
C) decreases

38. Which of these waves can not be polarized?
A) light
B) sound
C) electromagnetic
D) wave on a string

39. For standing waves, antinodes
A) are half a wavelength apart
B) have the greatest amplitude
C) alternate with nodes
D) all of the above

40. Like a transverse wave, a longitudinal wave also has
A) amplitude
B) wavelength
C) frequency
D) all of the above

41. Individual disturbance that make up a longitudinal wave
A) move perpendicular to the direction of the wave
B) move parallel to the direction of the wave
C) move in circles
D) move in ellipses

42. On a string that is 1.0 m long, standing waves may be formed with the following wavelengths:
A) 1.0 m, 2.0 m, 3.0 m
B) 1.0 m, 2.0 m, 4.0 m
C) 1.0 m, 0.67 m, 0.40 m
D) 1.0 m, 0.8 m, 0.75 m


43. On a string that is 1.0 m long, standing waves may be formed with the following wavelengths:
A) 1.0 m, 2.0 m, 3.0 m
B) 1.0 m, 2.0 m, 4.0 m
C) 3.0 m, 1.5 m, 0.75 m
D) 2.0 m, 1.0 m, 0.5 m


44. Two waves can pass through each other; this is described by or as
A) an elastic collision
B) an inelastic collision
C) a supersonic collision
D) superposition

45. Sound is a
A) polarized wave.
B) circular wave.
C) longitudinal wave.
D) transverse wave.

46. Sound
A) travels faster than light.
B) requires a medium.
C) is an electromagnetic wave.
D) all of the above.

47. Suppose you strike two tuning forks and hear a beat frequency of 2 Hz. You know that one of the tuning forks is tuned to 440 Hz. The other tuning fork must have a frequency of
A) 2 x 440 Hz = 880 Hz.
B) 440 Hz / 2 = 220 Hz
C) (440 + 2) Hz = 442 Hz
D) (440)2 = 193,600 Hz

48. If you double the frequency of a sound, you also double its
A) amplitude
B) wavelength
C) speed
D) all of the above
E) none of the above

49. The speed of sound in air depends upon
A) amplitude
B) frequency
C) temperature
D) wavelength

50. Sound travels fastest in
A) vacuum
B) air (gas)
C) water (liquid)
D) steel (solid)


PHY 3050G; Third Hour Exam, 10/27/00

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