Microsoft Word - sample_test4.docx
PHY 201 Sample Test 4 Name: ________________________
For the following questions, circle the one best answer. No explanation is required, but partial credit may be given for
explanations if provided.
1.
If the same fluid fills the containers shown, the pressures at the bases are related according to
which of the following expressions?
a) PC < PA < PE < PD < PB d) PE < PD = PC < PB < PA
) PE < PD < PC < PB < PA e) None of these is co
ect.
c) PA < PB < PC < PD < PE
2. A piping system that delivers a constant flow of water is constructed from pipes with different diameters as shown in
the figure. At which of the labeled points is the water in the pipe under the greatest pressure? The drawing is a view
from above the pipe.
a) A
) B
c) C
d) D
e) E
3. A mass is attached to a vertical spring and oscillates in simple harmonic motion. The elastic potential energy of the
system is greatest when it is at…
a) its highest point
) its equili
ium position
c) its lowest point
d) between its highest point and its equili
ium position
e) between its lowest point and its equili
ium position
4. In simple harmonic motion:
a) the acceleration is greatest at the maximum displacement
) the velocity is greatest at the maximum displacement
c) the period depends on the amplitude
d) the acceleration is constant
e) the acceleration is greatest at zero displacement
5. Complete the following sentence: Resonance occurs in harmonic motion when
a) the system is overdamped.
) the system is critically damped.
c) the energy in the system is a minimum.
d) the energy in the system is proportional to the square of the motion's amplitude.
e) the driving frequency is the same as the natural frequency of the system.
6. Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air,
a) the frequency remains the same but the wavelength is shorter.
) the frequency is higher but the wavelength stays the same.
c) the frequency is lower but the wavelength is longer.
d) the frequency is lower and the wavelength is shorter.
e) both the frequency and the wavelength remain the same.
7. In many cartoon shows, a character runs of a cliff, realizes his predicament and lets out a scream. He continues to
scream as he falls. If the physical situation is portrayed co
ectly, from the vantage point of an observer at the top of the
cliff leaning over the edge, the pitch of the scream should be
a) higher than the original pitch and constant.
) higher than the original pitch and increasing as he falls.
c) lower than the original pitch and constant.
d) lower than the original pitch and decreasing as he falls.
e) It is impossible to predict.
8. A block of material is floating in water. 30% of the object is visible above the surface of the water. The density of the
object as a percentage of the density of water is…
a) 15%
) 30%
c) 50%
d) 70%
e) 130%
9. The sound level in a room decreases by 20 dB. This means the sound intensity in the room decreased by a factor of…
a) 2
) 10
c) 20
d) 100
e) 1020
Problems: For each problem, show all work for full credit. Use at least three significant figures in your final answer.
Box or circle your final answer. Watch your units!
10. A 5.0 kg mass is attached to an ideal spring and oscillates in simple harmonic motion according to the equation:
? 0.040 ??? 30? ?/6
All units are SI.
a. Derive expressions for the velocity and acceleration of this oscillator as a function of time.
. What is the spring constant k for this oscillator?
c. What is the total mechanical energy of this oscillator?
11. A damped oscillator consists of a spring of constant 50 N/m attached to an 0.4 kg mass. The damping constant of the
spring is 0.0712 kg/s.
a. This oscillator is:
a) underdamped
) overdamped
c) critically damped
. If the oscillator has an initial amplitude of 5 cm, what is the amplitude of the system after 7 seconds have passed?
12. A travelling wave on a string has vertical displacement which obeys the relation:
? ?, ? 2/? ??? ?? – 400??
a. If the string has a linear density of 2 x 10‐4 kg/m, what is the tension in the string?
. What is the maximum speed of a particle on this string?
13. An loud explosion goes off, sending out sound waves uniformly in all directions. At your location, 500 m away, the
elative intensity level of the explosion is 112 decibels above the threshold of hearing (1 x 10‐12 W/m2). What is the total
sound power produced by the explosion?
14. A sample of material with mass 0.20 kg is found to float when placed in salt water (density 1025 kg/m3). Applying a
force of 3.7 N is just enough to hold the object completely under the waterline. What is the density of the sample?
Include a free body diagram with your work.
15. Water (density 1000 kg/m3) at a pressure of 1.01 x 105 Pa flows through a pipe of cross‐sectional area 1.50 cm2 with
a speed of 5.00 m/s. If the pipe widens to a cross‐sectional area of 6.00 cm2 (but does not change height), find the
esulting speed of the water flow and pressure in the wide part of the pipe.
16. A mass of 0.40 kg is hung from a spring with force constant 20.0 N/m and set oscillating. It moves from a maximum
height of 40.0 cm to a minimum of 10.0 cm and back.
a. Find the maximum acceleration of the mass. Where in the motion does this occur?
. What is the maximum kinetic energy of the mass? Where in the motion does this occur?
17. A standing wave on a sting is generated (as in your lab experiment) by an oscillator with a period of 0.0025 s. The
string is 1.5 m long and the standing wave forms a pattern with six antinodes (six loops). The string has a mass of 3.3 x
10‐3 kg. Determine the speed of the waves on the string, and the tension that has been applied to the string.
18. A criminal is fleeing police pursuit in a damaged car. The criminal’s car is moving away from the police car at 15 m/s,
while the police car pursues at 25 m/s. The police siren is producing a 1200 Hz tone. What frequency does the criminal
hear as he is being overtaken? The speed of sound is 343 m/s.
PHY 201 Sample Test 4 Name: ________________________
For the following questions, circle the one best answer. No explanation is required, but partial credit may be given for
explanations if provided.
3. A mass is attached to a vertical spring and oscillates in simple harmonic motion. The elastic potential energy of the
system is greatest when it is at…
4. In simple harmonic motion:
5. Complete the following sentence: Resonance occurs in harmonic motion when
6. Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air,
7. In many cartoon shows, a character runs of a cliff, realizes his predicament and lets out a scream. He continues to
scream as he falls. If the physical situation is portrayed co
ectly, from the vantage point of an observer at the top of the
cliff leaning over the edge, the pitch of the scream should be
8. A block of material is floating in water. 30% of the object is visible above the surface of the water. The density of the
object as a percentage of the density of water is…
9. The sound level in a room decreases by 20 dB. This means the sound intensity in the room decreased by a factor of…
Problems: For each problem, show all work for full credit. Use at least three significant figures in your final answer.
Box or circle your final answer. Watch your units!
10. A 5.0 kg mass is attached to an ideal spring and oscillates in simple harmonic motion according to the equation:
? 0.040 ??? 30? ?/6
All units are SI.
11. A damped oscillator consists of a spring of constant 50 N/m attached to an 0.4 kg mass. The damping constant of the
spring is 0.0712 kg/s.
a. This oscillator is:
. If the oscillator has an initial amplitude of 5 cm, what is the amplitude of the system after 7 seconds have passed?
12. A travelling wave on a string has vertical displacement which obeys the relation:
? ?, ? 2/? ??? ?? – 400??
13. An loud explosion goes off, sending out sound waves uniformly in all directions. At your location, 500 m away, the
elative intensity level of the explosion is 112 decibels above the threshold of hearing (1 x 10‐12 W/m2). What is the total
sound power produced by the explosion?
14. A sample of material with mass 0.20 kg is found to float when placed in salt water (density 1025 kg/m3). Applying a
force of 3.7 N is just enough to hold the object completely under the waterline. What is the density of the sample?
Include a free body diagram with your work.
15. Water (density 1000 kg/m3) at a pressure of 1.01 x 105 Pa flows through a pipe of cross‐sectional area 1.50 cm2 with
a speed of 5.00 m/s. If the pipe widens to a cross‐sectional area of 6.00 cm2 (but does not change height), find the
esulting speed of the water flow and pressure in the wide part of the pipe.
16. A mass of 0.40 kg is hung from a spring with force constant 20.0 N/m and set oscillating. It moves from a maximum
height of 40.0 cm to a minimum of 10.0 cm and back.
17. A standing wave on a sting is generated (as in your lab experiment) by an oscillator with a period of 0.0025 s. The
string is 1.5 m long and the standing wave forms a pattern with six antinodes (six loops). The string has a mass of 3.3 x
10‐3 kg. Determine the speed of the waves on the string, and the tension that has been applied to the string.