1 1 Physics 198 Final Exam-Solution December 16, 2008 The exam ...

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15. A mass m=0.25 kg is attached to an ideal spring and the mass-spring system
undergoes simple harmonic motion with no friction. If the mass is increased
by a factor of four to 1.0 kg, how will the frequency of oscillation change?
a. It does not change.
b. It goes up (faster oscillations) by a factor of four.
c. It does up (faster oscillations) by a factor of two.
d. ⇒It goes down (slower oscillations) by a factor of two
f = (1/(2π))*√(k/m) so multiplying m by 4 divides f by 2.
16. If the spring-mass simple harmonic system in Problem 13 has a spring
constant k = 10N/m and the mass is pulled 0.1 meters from equilibrium and
released at rest, what is the potential energy in Joules in the system just before
the mass is released?
a. ⇒ 0.05 PE = ½ k x 2 = ½*10*0.1*0.1 = 0.05
b. 0.10
c. 0.50
d. 1.00
e. 5.00
17. A sound pressure pulse is reflected from the closed end of a tube. The
reflected sound pulse is:
a. inverted (positive becomes negative)
b. ⇒ non-inverted (positive remains positive)
c. non-existent (pulse disappears at the tube end)
d. can be either inverted or non-inverted depending on the tube length.
18. The tube between the pinna and the eardrum is:
a. the Eustachian tube.
b. ⇒ the auditory canal.
c. the ossicles.
d. the stapes.
e. the cochlea.
19. In one to three clear sentences, explain the “place” theory of pitch.
⇒ The basilar membrane vibrates at different frequencies along its length, and
the brain knows what part is vibrating from sensor cells firing that have hairs
touching the membrane. Hence the “place” refers to the place on the
membrane that vibrates.
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