General Physics (PHYC 252) –Exam 1
Multiple Choice (60 points). Circle the one best answer for each question.
For Questions 1-8, refer to the diagram below showing a 4.0-kg mass, m, as it oscillates between x=A and
x=B. The position marked x=0 is the equilibrium position of the mass-spring system. The distance between A
and B is 0.50 m. A force of 6.0 N is required to stretch the spring from x = 0 to x = B when the oscillatory
motion is initiated. In simple harmonic motion, ω =
k
, where k is the spring constant and m is mass.
m
Assume frictionless contact between m and the surface on which it moves.
m
A
x=0
B
1. The amplitude of the SHM motion is:
(a) 1.00 m
(d) 0.25 m
(b) 0.75 m
(e) 0.10 m
(c) 0.50 m
(b) 12 N/m
(e) 2.0 N/m
(c) 6.0 N/m
(b) 0.39 s-1
(e) 3.56 s-1
(c) 1.54 s-1
2. The spring constant is:
(a) 24 N/m
(d) 3.0 N/m
3. The frequency (in Hz) is:
(a) 0.21 s-1
(d) 2.45 s-1
4. If the amplitude of the oscillations were decreased from what is indicated in the diagram, the frequency
would:
(a) decrease
(b) increase
(c) be unchanged
5. If the spring were replaced by one that is much stiffer, the period of oscillation would:
(a) decrease
(b) increase
(c) be unchanged
6. In the position that is shown for m in the diagram, i.e., exactly halfway between x=0 and x=A, the kinetic
energy is __________________ the elastic potential energy?
(a) more than
(b) less than
(c) equal to
7. At position B, velocity is _____________ and acceleration is _______________.
(a)
(b)
(c)
(d)
(e)
zero; zero
zero; at its most positive value
zero; at its most negative value
at its most positive value; at its most negative value
at its most negative value; at its most positive value
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8. What gives the total energy, KE + U, of the oscillating mass as it passes x=0?
1
kB
2
1
(d)
kB 2
2
1
kB
4
1 2
(e)
kB
2
(a)
(b)
(c)
1 2
kB
4
9. Which of the following relationships between acceleration a and displacement x of a particle produces
SHM?
(a) a = −10 x
(b) a = −10x 2
(d) a = 10x 2
(e) a =
(c) a = 10 x
10
x
10. A simple pendulum can be described to a good approximation as simple harmonic motion. The
approximation ____________ as the angle of oscillation decreases.
(a) improves
(b) becomes worse
(c) is unchanged
11. The diagram below shows the displacement of a pair of simple harmonic oscillators. They are phase
shifted from each other by:
x
t
3
π
2
1
(d) π
3
2
π
3
1
(e)
π
4
(a)
(b)
(c)
1
π
2
12. The diagram below gives a snapshot of a wave traveling in the negative x direction. At this instant in
time, what positions are moving upward?
A
B
D
C
x
E
(a) A and B only
(d) A, C, and E
F
(b) B and F only
(e) B, D, and F
(c) A and E only
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13. When a traveling wave is set up in a stretched string, the speed of the wave ___________ if the tension
in the string is reduced.
(a) increases
(b) decreases
(c) is unchanged
For Questions 14-19, consider the following four descriptions of waves set up in four different stretched
strings. The tension in each string is the same, but the mass densities, i.e., mass/length, are not necessarily the
same.
A:
B:
C:
D:
y = (4.0 cm)sin[(6.0π m-1)x-(2.0π s-1)t]
y = (6.0 cm)sin[(8.0π m-1)x-(4.0π s-1)t]
y = (2.0 cm)sin[(12.0π m-1)x-(12.0π s-1)t]
y = (3.0 cm)sin[(5.0π m-1)x-(10.0π s-1)t]
14. Which has the greatest amplitude?
(a) A
(b) B
(c) C
(d) D
(c) C
(d) D
(c) C
(d) D
(c) C
(d) D
(c) C
(d) D
15. Which has the fastest wave?
(a) A
(b) B
16. Which has the shortest wavelength?
(a) A
(b) B
17. Which has the longest period?
(a) A
(b) B
18. Which string has the greatest mass density?
(a) A
(b) B
19. For which string would individual string segments undergo the greatest maximum acceleration when a
complete wave cycle passed through?
(a) A
(b) B
(c) C
(d) D
20. A standing sound wave in a tube has three nodes and three antinodes. How many open ends does the pipe
have?
(a) none
(b) one
(c) two
Extra Credit
21. The sound intensity a distance x from the source of the sound is 4.0 µW/m2. What is the intensity at twice
the distance from the source?
(a) 1.0 µW/m2
(b) 2.0 µW/m2
(d) 8.0 µW/m2
(e) 16.0 µW/m2
(c) 4.0 µW/m2
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Problem Solving (60 points). Solve each problem in the space provided.
1. The displacement x(t) of a mass in simple harmonic motion is described by
π
x(t ) = (5.00 cm)cos[( s -1 )t + δ ] . We also know that at t = 2.40 s, x(t) = 4.20 cm.
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(a) What is the radial frequency of oscillation?
(b) What is the period of oscillation?
(c) What is the value of δ?
(d) What is the speed of the oscillating mass at t = 2.40 s?
2. A traveling transverse wave on a string is described by y(x,t) = (16.0 cm)sin[(10.0π m-1)x-(20.0π s-1)t].
(a) Find the velocity of the traveling wave.
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(b) Find the maximum transverse speed with which a particle on the string moves in the transverse
direction.
(c) Find the acceleration of a particle on the string at x=0 and t=π/3.
3. What is the sound level in B of noise with an intensity of 200 times the threshold value of 10-12 W/m2?
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