Physics Waves
A mass on a spring in SHM (Fig. 11-1) has amplitude A and periodT. At what point in the motion is the velocity zero and the acceleration zero simultaneously?
(e) None of the above.
A block of mass 0.4kg on a horizontal surface is attached to a horizontal spring of negligible mass. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. The block-spring system then experiences simple harmonic motion as described by the graph. The maximum spring potential energy of the block-spring system is most nearly
0.2 J
A block of mass M on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant 20N/m. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. When the block is pulled to a position beyond the spring's natural length and released from rest, the block experiences simple harmonic motion. A graph of the force exerted on the spring as a function of the block's position is shown. What is the spring potential energy stored in the spring-block system at position B?
0.4 J
A transverse periodic wave travels at a speed of 2m/s, along a string that is stretched along the horizontal axis. The graph shows the vertical position of a point on the string as a function of time. The frequency of the wave is nearly
0.5Hz
A transverse periodic wave travels at a speed of 2m/s, along a string that is stretched along the horizontal axis. The graph shows the vertical position of a point on the string as a function of time. What is the amplitude of the wave?
1.0m
(block situation in flashcard 36) At which of the following times does the spring exert its maximum force on the block?
2.0 s
A student attaches a 0.6kg block to a vertical spring so that the block-spring system will oscillate if the block-spring system released from rest at a vertical position that is not the system's equilibrium position. The student measures the velocity of the block as a function of time as the system oscillates, as shown in the graph. The spring constant of the spring is most nearly
2.6 N/m
A block on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant 30N/m. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. The block-spring system experiences simple harmonic motion, as shown in the graph. What is the change in spring potential energy of the block-spring system from when the block is released to when the block has its greatest speed?
240 J
One end of a string is wrapped around the end of a pulley and is securely connected to a hanging mass, and the other end of the string is fixed to a wave generator. The length of the string is L. The wave generator sends a wave through the string as shown in the figure. What is the wavelength of the wave?
2L/3
(block situation in flashcard 36) In one experiment, the students allow the block to oscillate after stretching the spring a distance A. If the potential energy stored in the spring is U0, then what is the change in kinetic energy of the block after it is released from rest and has traveled a distance of A2 ?
3/4U0
A transverse periodic wave travels along a string that is stretched along the x -axis. A small object of negligible mass is fixed at a point on the string. A graph of the object's vertical position as a function of time is shown in the graph. What is the amplitude of the wave?
3Y/2
A group of students conduct an experiment in which a 2.0kg block is secured on top of a vertical pole that has a spring around the pole. One end of a light, horizontal string of unknown length L is attached to the block and the other end is secured to a wall. A graph of the vertical position as a function of time for a single point on the string is shown.
5.0Hz
A hollow tube of length L0 is closed at one end and open at the end, as shown in the figure. The lowest-frequency standing wave that can be established in the tube has a frequency f0. The speed of a wave propagates at speed ν0. What is the frequency of the wave that corresponds to the third possible frequency above the fundamental frequency that will result in a standing wave?
5v0/4L0
A standing wave is created in a column of air inside of a tube that is open on both ends. The wave travels at 340m/s, and the length of the tube is 0.25m. What is the fundamental frequency of the wave?
680Hz
A student must determine the speed of sound in air by using the fundamental frequency of a standing wave. The student places a tuning fork in front of the open end of a pipe that is closed at the other end. The closed end of the pipe can be adjusted so that the length of the pipe can be changed. How should the student adjust the closed end of the pipe to determine the first standing wave that can be established in the pipe?
Adjust the closed end of the pipe so that it is the smallest distance away from the open end at which the largest sound level can be recorded by a sound level meter.
A sound wave is emitted from a speaker into the air. Which of the following models best predicts how energy is transferred by a sound wave from one air molecule to a second air molecule?
Air molecule 1 has a perfectly elastic collision with an adjacent air molecule 2. During the collision, kinetic energy is transferred from air molecule 1 to air molecule 2.
A block of mass 0.5kg on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant 50N/m. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. When the spring is unstretched, the block is located at x=0.0 m. The block is then pulled to x=0.5 m and released from rest so that the block-spring system oscillates between x=−0.5 m and x=0.5 m, as shown in figure 1. A free-body diagram of the object at a particular location is shown in figure 2. Based on the free-body diagram, at which of the following locations could the block be?
Between positions x=0.0 m and x=0.5 m
One end of a string is attached to a wall and the other end is held by a student's hand. The student creates the standing wave in the string that is shown in the figure. The student wants to change the standing wave so that a new standing wave is created. Which of the following claims describes a correct change that the student can make to the standing wave? Select two answers.
By decreasing the frequency of oscillation of the student's hand, the wavelength of the resulting standing wave will increase. By decreasing the frequency of oscillation of the student's hand, the period of the resulting standing wave will increase.
Students conduct an experiment in which two wave pulses travel toward each other along a horizontal string, as shown in the figure. Three locations, X, Y, and Z, are shown to represent the horizontal positions on the string where the waves travel. Each location is separated by a distance of 1.0m, and the wave speed for both wave pulses is 0.5ms. The width of each wave pulse is 1.0m. Which of the following figures represents the orientation of the wave pulses after 2.0s?
Can't insert pic because I don't have plus but its the one with only one wavelength that's really tall and looks like the man in the yellow hat's hat.
(experiment in flashcard 33) A student is asked to perform experiment 1, but with a spring of an unknown spring constant. The student performs four trials of the experiment with blocks of different mass and collects the data that are shown in the table. How should the student graphically analyze the data in order to determine the spring constant of the spring?
Create a graph with the period of oscillation plotted on the vertical axis and the square root of the mass of the block plotted on the horizontal axis. Use the slope of the best-fit line to determine the spring constant.
A block on a horizontal surface is attached to a horizontal spring of negligible mass, as shown in Figure 1. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. A group of students wants to investigate how stretching the spring within the block-spring system influences the motion of the system. For each trial of an experiment, the spring is stretched a variable distance Δx from its natural spring length, as shown in Figure 2, and blocks of different mass may be used. The block is then released from rest, and the system is allowed to oscillate. Figure 3 shows the horizontal position of the block as a function of time for one trial of the experiment. The students must conduct an experiment to determine the magnitude of the force exerted on the block when the block is at a position of A2, where A is the amplitude of oscillation for the block-spring system. For each trial, the students attach blocks of different mass m to the spring, stretch the spring a known distance A, release the system from rest, measure the period of oscillation T, and then measure the maximum velocity v of the system. How should students use a graph to determine the magnitude of the force under consideration?
Determine the magnitude of the slope of the best-fit line of T2 as a function of m. Multiply the result by A2.
Students conduct an experiment in which two wave pulses travel toward each other along a horizontal string, as shown in the figure. Three locations, X, Y, and Z, are shown to represent the horizontal positions on the string where the waves travel. Each location is separated by a distance of 1.0m, and the wave speed for both wave pulses is 0.5ms. The width of each wave pulse is 1.0m. Which of the following procedures would allow the students to collect data that could be used to quantify the amplitude variations that occur when the wave pulses interact?
Film the experiment with a slow-motion camera. Use a meterstick to assist with measuring the maximum height of each wave pulse before, during, and after the interaction.
One end of a horizontal string is attached to an oscillator, and the other end passes over a pulley and is connected to a hanging block that is used to keep the string taut. The oscillator can be adjusted to form different patterns of standing waves in the string of length L0. In an experiment, the students set the frequency of oscillation to a known value of f0 to create a standing wave. By collecting the appropriate data, the students determine that the speed ν of the wave is ν=2L0f05. How many nodes are on the string, and how do the known data justify that number of nodes on the string?
Five, because L0=5λ2L0=5λ2 where λλ is the wavelength.
A group of students use a slow-motion camera to film the oscillation of a point on a string as a wave generator is used create waves that propagate through the string. By using the film footage and the appropriate measuring techniques, students replicate the graph of the point's vertical position as a function of time that is shown in the figure. Which of the following quantities can the students determine from the graph? Select two answers.
Frequency Amplitude
A group of students must determine the frequency at which a wave generator is able to produce waves that propagate through strings of various length and mass. In an experiment, students test three different strings and collect the data that are shown in the table. Which of the following procedures could the students use to directly determine the frequency at which the waves are produced?
Graph the wave speed as a function of the wavelength and then determine the slope of the curve.
A student must determine the speed v of sound in air. The student places a tuning fork in front of the open end of a pipe that is closed at the other end. The closed end of the pipe can be adjusted so that the length of the pipe can be changed. The student varies the frequency of the sound in the pipe by holding tuning forks of different frequencies f in front of the open end of the pipe. The student then measures the smallest length L of the pipe that creates a standing wave for several different tuning forks. Which of the following procedures can the student use to determine the speed of sound in air by using a best fit line?
Graphing ff as a function of 1/L1/L and finding that the slope of the graph is equal to v/4v/4.
Student Y is at rest while sitting on a swing. Student X stands behind student Y and provides an initial applied force on student Y. Student Y's position on the swing then oscillates. Which of the following claims is correct about student Y?
If student X applies a greater force on student Y, the total mechanical energy of the student Y-Earth system will increase compared to the original situation.
One end of a string is attached to an oscillator and the other end passes over a pulley and is connected to a hanging block as shown in the figure. The oscillator can be adjusted to form different patterns of standing waves in the string. The students adjust the oscillator so that it makes the standing wave that is shown in the figure. The length of the string from the point where it is in contact with the pulley to the point where it is connected to the oscillator is L. Which of the following mathematical relationships can the students use to determine the wavelength λ of the string? Justify your answer.
L=λ2L=λ2, because only one half of a wavelength exists in the area where the string can oscillate.
One end of a string is secured to a wall while a student holds the other end of the string so that the string remains taut. The student shakes the end of the string vertically up and down so that a transverse wave is created on the string as it travels toward the wall. How can the student change the experiment, if at all, so that the wave speed of the wave increases?
None of the listed changes will increase the wave speed, because the speed of a wave is determined by the medium through which the wave propagates.
A student is given two tubes of length L. Tube X is open at both ends, and tube Y is open at one end and closed at the other end, as shown in the figure. A student must establish a standing wave in one of the tubes such that the relationship λ=2L, where λ represents the wavelength of the wave, is verified if the speed of sound in air is known. The student uses tube Y and places a variable frequency generator in front of the open ends. The student determines that λ=4L rather than λ=2L for a given frequency. How can the student refine the experiment to verify that λ=2L ?
Perform the experiment with tube XX rather than tube YY.
A group of students are asked to determine the speed of sound in air. The students use a tube that is open at both ends and places the tube in the water so that it is completely submerged. The students place a sound wave generator of a fixed frequency above the tube so that standing waves can be established in the tube when the top of the tube is raised above the water line, as shown in the figure. The students raise the top of the tube above the water line until they determine the first location at which the intensity of the sound is at a maximum, which is a distance L above the water line. After performing their calculations, the students determine the speed of sound to be nearly 172m/s. The students are informed that the speed of sound is nearly 343m/s. How should the students refine their data analysis so that the correct speed of sound can be determined?
Recalculate the wavelength λλ of the standing wave as λ=4Lλ=4L.
A student must use an object attached to a string to graphically determine the gravitational field strength near Earth's surface. The student attaches the free end of the string to the ceiling and pulls the object-string system so that the string makes an angle of 5 degrees from the object's vertical hanging position. The student then releases the object from rest and uses a stopwatch to measure the time it takes for the object to make one complete oscillation. Which of the following is the next step that will allow the student to determine the gravitational field strength?
Repeat the experiment by changing the length of the string for multiple trials.
Two identical wave pulses, pulse X and pulse Y, are created at opposite ends of a horizontal string and are moving toward each other, both at speed of 1cm/s. The horizontal positions along the string are shown in the figure. Also, the figure shows the position of the pulses at time t=0. Which of the following figures most accurately depicts the shape of the string at t=2.5s?
Still don't have plus so it's the graph that has the tallest/skinniest rectangle
A block on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant k0. The other end of the spring is attached to a wall. When the spring is unstretched, the block is located at x=0m, as shown in Figure 1. The block is then pulled to x=0.3m and released from rest so that the block-spring system oscillates between x=−0.3m and x=0.3m. A student creates the graph shown in Figure 2, which shows the kinetic energy of the block-spring system as a function of the block's position. Which of the following mathematical routines can a student use, if at all, to determine the approximate change in the spring potential energy of the block-spring system when the block is moved from a position of x=0.00m to x=0.02m ?
Subtract the kinetic energy of the block at x=0.02m from the kinetic energy of the block at x=0.00m.
A block of mass M on a horizontal surface is attached to a horizontal spring of negligible mass. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. When the block is pulled to a position beyond the spring's natural length and released from rest, the block experiences simple harmonic motion. A graph of the force exerted on the spring as a function of the block's position is shown. A student collects data such that the force that the spring exerts on the block for every 0.25s is plotted on the graph that is shown. Which two of the following claims is correct about the block-spring system during the time in which data were collected? Select two answers.
The block has its maximum acceleration at all times 0.5n, where n is a zero or a whole number. The block has maximum spring potential energy at all times 0.5n, where n is a zero or a whole number.
A group of students conduct an experiment in which a 2.0kg block is secured on top of a vertical pole that has a spring around the pole. One end of a light, horizontal string of unknown length L is attached to the block and the other end is secured to a wall. A graph of the vertical position as a function of time for a single point on the string is shown. One of the students in the group makes the following claim. "If all other aspects of the experimental setup are held constant, only specific changes in the length of the string can produce a new standing wave." Is the claim correct, and what evidence supports your answer?
The claim is correct. A new standing wave will be established only if the length of the string is L±nλ2>0L±nλ2>0, where nn is a whole number.
A 4.0 kg cube is placed in a container of water. A student observes that the cube floats. The net force exerted on the cube F represents the sum of the force due to gravity and the force exerted on the cube by the water. A force probe is used to measure F as a function of the cube's distance y from the bottom of the container. The graph shows F as a function of y, where the positive direction is upward. Which of the following statements is correct about the motion of the cube if it is released from rest at a vertical position of y=0.05 m?
The cube will oscillate between y=0.05 m and y=0.09 m.
A student stands a large distance away from a speaker than can emit sound. The speaker initially emits sound waves of amplitude A1 that propagate through the air with speed v1 whenever the waves reach the student's ear. The student is unable to hear the sound waves. The speaker then emits sound of amplitude A2 that propagate through the air with speed v2 whenever the waves reach the student's ear. The student is able to hear the sound waves. Which of the following claims are correct about why the student can hear the second set of sound waves but not the first set? Justify your selection.
The energy contained in the second set of sound waves is greater than the energy contained in the first set. Therefore, A2>A1A2>A1 and v2=v1v2=v1.
A block of mass M hangs at rest at the bottom of a stationary spring that stretches a distance A from the spring's unstretched length. The block is then pulled down an additional distance A so the spring is stretched a distance 2A , as shown in the figure. The block is released from rest, and the center of mass of the block vertically oscillates a displacement of 2A from its lowest position to its highest position. The lowest vertical position of the block's center of mass is the location at which the gravitational potential energy of the block-spring-Earth system is zero. Which two of the following claims are correct about the mechanical energy of the system? Select two answers.
The kinetic energy of the block is at its maximum when the spring is stretched a distance A from its unstretched length. The potential energy of the system is at its maximum when spring is stretched a distance 2A from its unstretched length.
Student X attaches an object of mass M to the end of a string of length L so that a pendulum is constructed. Student Y attaches an object of mass M to a string of length 4L to construct a second pendulum. Which of the following claims correctly compares the period of Student X's pendulum with the period of Student Y's pendulum?
The period of Student X's pendulum is half the period of Student Y's pendulum.
The gravitational field strength near Jupiter's surface is nearly 2.53 times greater than the gravitational field strength near Earth's surface. Which of the following claims is correct about the period of a pendulum if it oscillates near Jupiter's surface and near Earth's surface?
The period of the pendulum will be greater on Earth.
(experiment in flashcard 33) The students conduct experiment 2 in which the same block is connected to the same spring on a horizontal surface. The spring is stretched a distance L2 beyond its natural length and released from rest, allowing the block-spring system to oscillate. Frictional forces are considered to be negligible. Which of the following claims is correct about how the period of oscillation for the block-spring system in experiment 2 compares with the period of oscillation for the system in experiment 1, and what evidence supports the claim?
The periods of oscillation for experiment 2 and experiment 1 are the same, because the block and the spring used in both experiments are identical.
A group of students conduct an experiment to study standing waves within a tube. The students use two tubes that are identical except for their slightly different lengths. Both tubes have one open end and one closed end. A speaker connected to a variable frequency generator is placed in front of the tubes, as shown. A student makes the following claim, "When the frequency is adjusted to produce a standing wave in one tube, the same standing wave will be produced in the other tube." Which of the following claims is correct about the student's statement? Justify your selection.
The student is incorrect because the length of each tube, along with the emitted frequency, determines if a standing wave is produced.
Students conduct an experiment in which two wave pulses travel toward each other along a horizontal string, as shown in the figure. Three locations, X, Y, and Z, are shown to represent the horizontal positions on the string where the waves travel. Each location is separated by a distance of 1.0m, and the wave speed for both wave pulses is 0.5ms. The width of each wave pulse is 1.0m. Which of the following claims, with supporting evidence, is correct about wave pulse 1?
The student who created the pulse created a transverse wave, because the student had to shake the end of the string up and down.
A student attaches a block to a vertical spring so that the block-spring system will oscillate in simple harmonic motion if the system is released from rest at a vertical position that is not the system's equilibrium position. Which of the following explanations is correct about why the system oscillates in simple harmonic motion about the block-spring system's equilibrium position?
The system oscillates in simple harmonic motion because the block's acceleration is directly proportional to and opposite in direction to the block's displacement from the system's equilibrium position.
One end of a string is secured to a wall while a student holds the other end of the string so that the string remains taut. The student shakes the end of the string vertically up and down so that a transverse wave is created on the string as it travels toward the wall. Which of the following can another student measure to determine the speed of the wave? Select two answers.
The time it takes for a single wavelength to pass through a particular point The distance between one crest and an adjacent crest
In an experiment, a tubular musical instrument is played such that standing waves are established inside of the tube. A student is provided with the data in the table, which contains information about the length of the tube and the fundamental frequency at which the standing wave is established. The speed of sound in air is considered to be 340m/s. Which of the following statements is correct about the type of tube that was used in the experiment?
The tube is open at one end and closed at the other end.
One end of a vertical spring is secured to the ceiling, and the other end is connected to a device that can send wave pulses through the spring by vibrating up and down, as shown in the figure. When the device is turned on, which of the following explanations is correct about the resulting wave that travels through the spring?
The wave is longitudinal because the wave propagates in a direction that is along the same line of motion as the block-spring system.
A group of students conduct an experiment in which a 2.0kg block is secured on top of a vertical pole that has a spring around the pole. One end of a light, horizontal string of unknown length L is attached to the block and the other end is secured to a wall. A graph of the vertical position as a function of time for a single point on the string is shown. The period of oscillation for the block on the spring is increased so that a new standing wave is produced, but the length of the string is held constant at length L. Which of the following claims about the new standing wave is correct?
The wavelength of the standing wave will increase.
Two students hold a string taut between them. They each send two wave pulses toward each other so that wave interference may be studied. By filming the experiment with a slow-motion camera, the students create the graph shown of each wave pulses' vertical position as a function of their horizontal position. Each wave pulse travels with a speed of 10cm/s. At what time will the center of each wave pulse be at the same position, and what will the resultant amplitude be at this time?
Time: .3s RA: 2cm
A block on a horizontal surface is attached to a horizontal spring of spring constant 50N/m. The other end of the spring is attached to a wall. The block is initially at the equilibrium position of the block-spring system, as shown in the figure. The block is then moved to a position of x=60cm and released from rest so that the system oscillates. A student predicts the kinetic energy of the block-spring system as a function of the block's horizontal position as shown in Graph 1. When an experiment is conducted, the block does not make a complete oscillation because frictional forces were not considered in the student's prediction. Data is collected about the actual kinetic energy of the block-spring system as a function of the block's horizontal position and is used to create Graph 2. How can the student use one or both graphs to determine how much mechanical energy is converted to nonmechanical energy from the instant the block is released from rest to the instant that the block is no longer in motion?
Use Graph 2 to determine the spring potential energy stored in the system at the instant the block is no longer in motion. Subtract this value from the maximum predicted kinetic energy of the block that can be determined from Graph 1.
A transverse periodic wave travels at a speed of 2m/s, along a string that is stretched along the horizontal axis. The graph shows the vertical position of a point on the string as a function of time. If the frequency of the wave is doubled, what is the resulting wavelength and period of the wave?
Wavelength: 2.0 m Period: 1.0 s
A student plays an instrument that has a string fixed at two locations. When the string is plucked, standing waves can be established on the string. The student must determine the speed of the standing waves that are generated on the string. The student performs a series of experiments to determine the fundamental frequency of the standing waves on the string after the length of string has been changed and the string has been plucked. A graph of the fundamental frequency as a function of the inverse of the string length is shown. Can the graph be used to determine the speed of the standing waves on the string?
Yes, because the slope of a best-fit line will be equal to half the speed of the standing wave.
1. Do you expect an echo to return to you more quickly on a hot day or a cold day! (a) Hot day (b) Cold day () Same on both days
a
10. An organ pipe with a fundamental frequency f is open at both ends. If one end is closed off, the fundamental fre quency will (a) drop by half. (b) not change. (c) double.
a
10. Two waves are traveling toward each other along a rope. When they meet, the waves (a) pass through each other. (b) bounce off of each other. (c) disappear.
a
15. A wave transports (a) energy but not matter. (b) matter but not energy. (c) both energy and matter.
a
8. A grandfather clock is losing time because its pendulum moves too slowly. Assume that the pendulum is a massive bob at the end of a string. The motion of this pendulum can be sped up by (list all that work (a) shortening the string. (b) lengthening the string. (c) increasing the mass of the bob. (d) decreasing the mass of the bob.
a
2 An object oscillates back and forth on the end of a spring. Which of the following statements are true at some time during the course of the motion? (a) The object can have zero velocity and, simultaneously. nonzero acceleration. (b) The object can have zero velocity and, simultaneously: zero acceleration (c) The object can have zero acceleration and, simultaneously, nonzero velocity. (d) The object can have nonzero velocity and nonzero acceleration simultaneously.
a,c,d
3. The sound level near a noisy air conditioner is 70 dB. If two such units operate side by side, the sound level near them Would be (a) 70 dB. (b) 73 dB. (c) 105 dB (d) 140 dR
b
4. An object of mass m rests on a frictionless surface and is attached to a horizontal ideal spring with spring constant k. The system oscillates with amplitude A. The oscillation frequency of this system can be increased by (a) decreasing k. (b) decreasing m. (c) increasing A. (d) More than one of the above. (e) None of the above will work.
b
11. Two loudspeakers are about 10 m apart in the front of a large classroom. If either speaker plays a pure tone at a single frequency of 400 Hz, the loudness seems pretty even as you the wander around the room, and gradually decreases in volume as you move farther from the speaker. If both speakers then play the same tone together, what do you hear as you wander around the room? (a) The pitch of the sound increases to 800 Hz, and the sound is louder but not twice as loud. It is louder closer r to the speakers and gradually decreases as you move away from the speakers-except near the back wall where a slight echo makes the sound louder. (b) The sound is louder but maintains the same relative spatial pattern of gradually decreasing volume as you move away from the speakers (c) As you move around the room, some areas seem to be dead spots with very little sound, whereas other spots seem to be louder than with only one speaker. (d) The sound is twice as loud-so loud that you cannot hear any difference as you move around the room. (e) At points equidistant from both speakers, the sound is twice as loud. In the rest of the room, the sound is the same as if a single speaker were playing.
c
12. You are driving at 75 km/h. Your sister follows in the car behind at 75 km/h. When you honk your horn, your sister hears a frequency (a) higher than the frequency you hear. (b) lower than the frequency you hear. (c) the same as the frequency you hear. (d) You cannot tell without knowing the horn's frequency
c
14. A student attaches one end of a Slinky to the top of a table. She holds the other end in her hand, stretches it to a length, and then moves it back and forth to send a wave down the Slinky. If she next moves her hand faster while keeping the length of the Slinky the same, how does the wavelength down the Slinky change? (a) It increases. (b) It stays the same. (c) It decreases.
c
3. An object of mass M oscillates on the end of a spring. To double the period, replace the object with one of mass: (a) 2M. (b) M/2. (c) 4M. (d) M4 (e) None of the above.
c
7. At a playground, two young children are on identical swings One child appears to be about twice as heavy as the other. If you pull them back together the same distance and release them to start them swinging, what will you notice about the oscillations of the two children? (a) The heavier child swings with a period twice that of the lighter one. (b) The lighter child swings with a period twice that of the heavier one. (c) Both children swing with the same period.
c
9. A guitar player shortens the length of a guitar's vibrating string by pressing the string straight down onto a fret. The guitar then emits a higher-pitched note, because (a) the string's tension has been dramatically increased. (b) the string can vibrate with a much larger amplitude. (c) the string vibrates at a higher frequency.
c
11. Which of the following increases the speed of waves in a stretched elastic cord? (More than one answer may apply.) (a) Increasing the wave amplitude. (b) Increasing the wave frequency (c) Increasing the wavelength. (d) Stretching the elastic cord further.
d
12. Consider a wave on a string moving to the right, as shown in Fig. 11-50. What is the direction of the velocity of a particle of string at point B? Wave velocity (a) (b) (c) + (d) 4 (e) v = 0, so no direction.
d
13. What happens when two waves, such as waves on a lake, come from different directions and run into each other? (a) They cancel each other out and disappear. (b) If they are the same size, they cancel each other out and disappear. If one wave is larger than the other, the smaller one disappears and the larger one shrinks but continues. (c) They get larger where they run into each other; then they continue in a direction between the direction of the two original waves and larger than either original wave. (d) They may have various patterns where they overlap. but each wave continues with its original pattern away from the region of overlap. (e) Waves cannot run into each other, they always come from the same direction and so are parallel.
d
2 Sound waves are (a) transverse waves characterized by the displacement of air molecules (b) longitudinal waves characterized by the displacement of air molecules. (c) longitudinal waves characterized by pressure differences (d) Both (b) and (c). (e) (a), (b), and (c).
d
13. A guitar string is vibrating at its fundamental frequency f. Which of the following is not true? (a) Each small section of the guitar string oscillates up and down at a frequency f. (b) The wavelength of the standing wave on the guitar string is A = v/f. where e is the velocity of the wave on the string (c) A sound wave created by this vibrating string propagates through the air with frequency f. (d) A sound wave created by this vibrating string propagates through the air with wavelength A = v/f. where is the velocity of sound in air. v (e) The wavelength of the standing wave on the guitar string is where is the length of the string.
e
4. To make a given sound seem twice as loud, how should a musician change the intensity of the sound? (a) Double the intensity. (b) Halve the intensity (c) Quadruple the intensity, (d) Quarter the intensity. (e) Increase the intensity by a factor of 10
e
6. In which of the following is the wavelength of the lowest vibration mode the same as the length of the string or tube? (a) A string () An open tube. (e) A tube closed at one end. (d) All of the above. () None of the above.
e
6. Suppose you pull a simple pendulum to one side by an angle of 5. let go, and measure the period of oscillation that ensues. Then you stop the oscillation, pull the pendu lum to an angle of 10°, and let go. The resulting oscillation will have a period about the period of the first oscillation. (a) four times (b) twice (c) half (d) one-fourth (e) the same as
e
7. When a sound wave passes from air into water, what prop erties of the wave will change? (a) Frequency. (b) Wavelength. (e) Wave speed. (d) Both frequency and wavelength. (e) Both wave speed and wavelength.
e
8. A guitar string vibrates at a frequency of 330 Hz with wave length 1.40 m. The frequency and wavelength of this sound in air (20°C) as it reaches our cars is (0) same frequency, same wavelength. (b) higher frequency, same wavelength. (c) lower frequency, same wavelength. (d) same frequency, longer wavelength. (e) same frequency, shorter wavelength.
e
9. Consider a wave traveling down a cord and the transverse motion of a small piece of the cord. Which of the following is true? (a) The speed of the wave must be the same as the speed of a small piece of the cord. (b) The frequency of the wave must be the same as the frequency of a small piece of the cord. (c) The amplitude of the wave must be the same as the amplitude of a small piece of the cord. (d) All of the above are true. (e) Both (b) and (c) are true.
e
In experiment 1, a block of mass M is attached to the end of vertical spring of spring constant k0 with its free end at vertical position L0, as shown in Figure 1. The mass of the spring is considered to be negligible. When the block is attached to the spring and is at rest at the block-spring's equilibrium position, the spring is stretched so that its end is at a new position L1, as shown in Figure 2. The block is then pulled down to a new vertical position L2 and then released from rest so that the block-spring system oscillates. Assume that the reference line for zero gravitational potential energy of the system is at the lowest point in the system's vertical displacement from equilibrium. The experiment is assumed to be performed near Earth's surface. What is the magnitude of the change in potential energy of the block-spring system when it travels from its lowest vertical position to its highest vertical position?
k0L1L2
A student attaches a block to a vertical spring so that the block-spring system will oscillate if the block-spring system is released from rest at a vertical position that is not the system's equilibrium position. Which of the following measuring tools, when used together, can be used to determine the spring constant of the spring? Select two answers.
stopwatch, electronic balance
5. A musical note that is two octaves higher than a second note (a) has twice the frequency of the second note. (b) has four times the frequency of the second note. (c) has twice the amplitude of the second note. (4) is 3 dB louder than the second note. (e) None of the above
x
5. When you use the approximation sine for a pendulum. (b) degrees only. you must specify the angle in (a) radians only. (c) revolutions or radians (d) degrees or radians
x?
