Name:______________________________Class:__________________ Date:__________________ Assessment Chapter Test B Teacher Notes and Answers Vibrations and Waves CHAPTER TEST B (ADVANCED) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. b d b b c c c d b c a b d The restoring force in a swinging pendulum is a component of the gravitational force acting on the pendulum bob. three Moving the pendulum bob down increases the length of the pendulum. As a result, the period of the pendulum increases and the frequency decreases. The water wave is a disturbance moving through the water, but the water (the medium) is not carried forward with the wave. A pulse wave is a single traveling disturbance resulting from a motion that is not repeated. A periodic wave is one whose source is repeated motion. The amplitude increases. (complete) destructive 200 N/m Given x = 0.1 m 22. 1.5 s Given mtotal = 1500 kg k (per spring) = 6600 N/m Solution Assume that the total mass of 1500 kg is supported equally on the four springs. Each spring then supports 1500 kg/4. m 1500 kg/4 = 2 = 1.5 s k 6600 N/m T = 2 23. 21.7 kg Given Tpendulum = 3.45 s k = 72.0 N/m Solution If both systems have the same frequency, they will also have the same period. Therefore, the given period may be substituted into the equation for a massspring system. m k m T 2 = 4 2 k T = 2 m= T 2k 2 = (3.45 s)2 (72.0 N/m) 4 m = 21.7 kg 24. 2.91 m Given f = 103.1 MHz 4 2 = v = 3.00 108 m/s Solution f = 103.1 MHz = 1.031 108 Hz Felastic = 20 N Solution Felastic = kx v = f k = Felastic /x = v/f = (3.00 103 m/s)/ k = 20 N/ 0.1 m = 200 N/m (1.031 108 Hz) = 2.91 m Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ 1 Chapter Tests Name:______________________________Class:__________________ Date:__________________ 25. 0.80 m Given L = 2.0 m The standing wave has 5 antinodes, i.e., 5 loops. Solution A single loop (antinode) is produced by a wavelength equal to 2L. Two loops (one complete wavelength) are produced by a wavelength of L. A wavelength of 2/3 L results in 3 antinodes. The following pattern emerges: 1 loop = 2L/1 = 2L 2 loops = 2L/2 = L 3 loops = 2L/3 = 2/3 L 4 loops = 2L/4 = 1/2 L 5 loops = 2L/5 = 2/5 L 2/5 2.0 m = 0.80 m Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ 2 Chapter Tests Name:______________________________Class:__________________ Date:__________________ Assessment Vibrations and Waves Chapter Test B MULTIPLE CHOICE In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. _____ 1. Vibration of an object about an equilibrium point is called simple harmonic motion when the restoring force is proportional to a. time. c. a spring constant. b. displacement. d. mass. _____ 2. A mass-spring system can oscillate with simple harmonic motion because a compressed or stretched spring has what kind of energy? a. kinetic c. gravitational potential b. mechanical d. elastic potential _____ 3. A pendulum swings through a total of 28°. If the displacement is equal on each side of the equilibrium position, what is the amplitude of this vibration? (Disregard frictional forces acting on the pendulum.) a. 28° c. 56° b. 14° d. 7.0° _____ 4. If a pendulum is adjusted so that its frequency changes from 10 Hz to 20 Hz, its period will change from n seconds to a. n/4 seconds. c. 2n seconds. b. n/2 seconds. d. 4n seconds. _____ 5. By what factor should the length of a simple pendulum be changed in order to triple the period of vibration? a. 3 c. 9 b. 6 d. 27 _____ 6. Each stretched region in the waveform of the longitudinal wave shown on the right corresponds to what feature of the transverse wave below it? a. wavelength b. crests c. troughs d. amplitude Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ 3 Chapter Tests Name:______________________________Class:__________________ Date:__________________ Chapter Test B continued _____ 7. Suppose that two sound waves passing through the same medium have different wavelengths. Which of the following is most likely to be the reason for the differing wavelengths? a. the nature of the medium c. differences in frequency b. differences in amplitude d. the type of wave _____ 8. When a mechanical wave’s amplitude is reduced by half, the energy the wave carries in a given time interval is a. doubled. c. decreased to one-half. b. increased by a factor of 1.4. d. decreased to one-fourth. _____ 9. Two waves traveling in opposite directions on a rope meet and undergo complete destructive interference. Which of the following best describes the waves a moment after the waves meet and coincide? a. The waves no longer exist. b. The waves continue unchanged. c. The waves reflect and travel backward. d. A single wave continues along the rope. _____ 10. Which of the following types of interference will occur when the pulses in the figure above meet? a. no interference c. partial destructive b. complete constructive d. complete destructive _____ 11. Consider two identical wave pulses on a rope having a fixed end. Suppose the first pulse reaches the end of the rope, is reflected back, and then meets the second pulse. When the two pulses overlap exactly, what will be the amplitude of the resultant pulse? a. zero b. same as the original pulses c. double the amplitude of the original pulses d. half the amplitude of the original pulses _____ 12. A 2.0 m long stretched rope is fixed at both ends. Which wavelength would not produce standing waves on this rope? a. 2.0 m c. 4.0 m b. 3.0 m d. 6.0 m Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ 4 Chapter Tests Name:______________________________Class:__________________ Date:__________________ Chapter Test B continued _____ 13. A 3.0 m long stretched string is fixed at both ends. If standing waves with a wavelength of two-thirds L are produced on this string, how many nodes will be formed? a. 0 c. 3 b. 2 d. 4 SHORT ANSWER 14. In an oscillating mass-spring system, the restoring force is a result of the force exerted by the spring. What causes the restoring force in a swinging pendulum? _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ 15. If a spring is stretched from a displacement of 10 cm to a displacement of 30 cm, the force exerted by the spring increases by a factor of ___________. _______________________________________________________________ 16. In an old-fashioned pendulum clock, the bob is moved up and down to adjust the clock to keep accurate time. How would you adjust the bob in order to correct a clock that runs too fast? Explain why the adjustment works. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ 17. A boat produces a wave as it passes an aluminum can floating in a lake. Explain why the can is not moved along in the direction of wave motion. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ 18. What is the difference between a pulse wave and a periodic wave? _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ 5 Chapter Tests Name:______________________________Class:__________________ Date:__________________ Chapter Test B continued 19. What feature of a wave increases when the source of vibration increases in energy? _______________________________________________________________ 20. A standing wave is produced by plucking a string. The points along the plucked string that appear not to be vibrating are produced by _____________ interference. _______________________________________________________________ PROBLEM 21. A mass on a spring that has been compressed 0.1 m has a restoring force of 20 N. What is the spring constant? 22. A car with bad shock absorbers bounces up and down after hitting a bump. The car has a mass of 1500 kg and is supported by four springs, each having a spring constant of 6600 N/m. What is the period for each spring? 23. A student wishes to construct a mass-spring system that will oscillate with the same frequency as a swinging pendulum with a period of 3.45 s. The student has a spring with a spring constant of 72.0 N/m. What mass should the student use to construct the mass-spring system? 24. Radio waves from an FM station have a frequency of 103.1 MHz. If the waves travel with a speed of 3.00 108 m/s, what is the wavelength? 25. Vibration of a certain frequency produces a standing wave on a stretched string that is 2.0 m long. The standing wave has 7 nodes and 5 antinodes. What is the wavelength of the wave that produces this standing wave? Original content Copyright © by Holt, Rinehart andCourseHero.com Winston. Additionson and06-21-2022 changes to the original GMT content-05:00 are the responsibility of the instructor. This study source was downloaded by 100000849057121 from 15:22:59 Holt Physics https://www.coursehero.com/file/61055236/hssp1100t-chaptestbpdf/ Powered by TCPDF (www.tcpdf.org) 6 Chapter Tests