1. Chapter 11-12 Review

2. Ch. 11 page 396-398 1, 4, 7, 8, 12, 14, 16, 19, 21, 23-25, 31, 32, 35, 37, 41, 42 1. Oscillation about an equilibrium position in which a restoring force is proportional to displacement. 4. No. A pendulum’s displacement is approximately proportional to its restoring force only at angles smaller than 15 degrees. 7. The tangent component (F gx ); because it always pulls the bob toward the equilibrium position 8. see solution page

3. Ch. 11 page 396-398 1, 4, 7, 8, 12, 14, 16, 19, 21, 23-25, 31, 32, 35, 37, 41, 42 12. The period and frequency are inversely related. 14. There would be no change in frequency or period because the frequency or period does not depend on the pendulum’s mass. 16. If it is running slow, make the pendulum length longer. 19. see solution page 21. see solution page

4. Ch. 11 page 396-398 1, 4, 7, 8, 12, 14, 16, 19, 21, 23-25, 31, 32, 35, 37, 41, 42 23. For a transverse wave, the vibration direction is perpendicular to wave travel. For a longitudinal wave, the vibration direction is parallel or in the same direction as wave travel. 24. a the particles are moving up and down b) the wave is transverse 25. This is a longitudinal wave (compressions and rarefactions) 31. Sound waves are mechanical waves, which are produced by the displacement of particles. Without matter, no propagation of wave energy occurs.

5. Ch. 11 page 396-398 1, 4, 7, 8, 12, 14, 16, 19, 21, 23-25, 31, 32, 35, 37, 41, 42 32. Neither. Wave speed depends only upon the medium which is travels through (solid, liquid, gas or vacuum) 35. see solutions page 37. In constructive interference, individual displacements are on the same side of the equilibrium position. In destructive interference, the individual displacements are on opposite sides of the equilibrium position. 41. The resultant displacement is zero (totally cancels at that position) 42. Yes. When interference is constructive.

6. Ch. 11 page 400--401 STP (1-5, 7-18). 1. C 2. J (see solution page) 3. C 4. F 5. C 7. B 8. G 9. A [12 cycles/120 sec] 10. H (see solution page) 11. A 12. H 13. A 14. J [.75 m +.53 m] 15. A [.75 m -.53 m] 16. G (see solution page) 17. (see solution page) 18. electromagnetic waves

7. Ch. 12 page 434-435 3, 4-6, 8, 9, 11, 13, 16, 18, 22, 23, 25, 27, 38, 40a 3. Frequency measure of the rate of particle vibrations (# of vibrations per second is Hz). Pitch is the frequency of a sound wave as experienced by the listener. 4. infrasonic is less than 20 Hz, audible is between 20-20,000 Hz, and ultrasonic is above 20,000 Hz. 5. The speed of any wave changes as the medium changes. A temperature increase makes the air molecules move faster, so it is easier to transfer sound waves. 6. You know when the ambulance passes when you hear the pitch of the siren drop from higher to lower. 8. If wavelength decreases by 2 times, then the frequency will increase by 2 times (inverse relationship). Since wave speed depends only on the medium, there is no change in wave speed unless the medium changes.

8. Ch. 12 page 434-435 3, 4-6, 8, 9, 11, 13, 16, 18, 22, 23, 25, 27, 38, 40a 9. Sound waves (or mechanical waves) travel faster through solids than through gases. 11. The driver of the van in front of the ambulance, because the source of the waves (siren) is approaching the observer. 13. Intensity is the measure of power per unit area (W/m 2 ). Decibel level is related to how we perceive loudness (dBs), which is relative intensity. 16. Resonance occurs when the forced vibration matches the natural frequency (or frequencies) of a substance or vibrating system. 18. 10 dB difference means 10 times louder; so nine machines could be added (10 units = 10 dB increase)

9. Ch. 12 page 434-436 3, 4-6, 8, 9, 11, 13, 16, 18, 22, 23, 25, 27, 38, 40a 22. see solution page 23. see solution page 25. L = 2.0 m, so a) 4.0 m (2L) b) 2.0 m (L) c) 1.3 m (2/3L) d) 1.0 m (1/2L) 27. The two different instruments have different harmonics present at different intensities. 38. see solution page 40a see solution page

10. Ch. 12 page 438-439 STP (1-11, 14, 17-19) 1. B 2. J 3. D 4. H (10 3 is 30 dB increase) 5. C 6. F 7. B 8. G (see solution page) 9. D 10. G (see solution page) 11. 7 beats per second 14. see solution page 17. see solution page 18. see solution page 19. see solution page