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Physics 1) The speed of sound in a certain metal block is 3

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Physics

1) The speed of sound in a certain metal block is 3.00 x ?10 ³ m/s. The graph shows the amplitude (in meters) of a wave traveling through the block versus time (in milliseconds). What is the wavelength of this wave?

1. 0.5 m                           (d) 4.0 m
2. 1.5 m                           (e) 6.0 m
3. 3.0 m

 

2.         What is the wavelength of a wave with a speed of 12 m/s and a period of 0.25 s?    

(a) 0.25 m                                (c) 3.0 m                        (e) 48 m (b) 1.5 m                                  (d) 24 m 

 

  

 The displacement of a vibrating string versus position along the string is shown in the figure.

The periodic waves have a speed of 10.0 cm/s. A and B are two points on the string.

 

 

3.What is the amplitude of the wave?       

 

1. 1. 2 cm
   2. 4 cm
   3. 8 cm
   4. 12 cm
   5. 16 cm

 

 

 

  

4. What is the wavelength of the wave?              
   1. 3.0 cm                         (c) 9.0 cm                          (e) 15 cm (b) 6.0 cm                         (d) 12 cm

 

5. What is the frequency of the wave?    
   1. 0.60 Hz                          (c) 1.1 Hz                     (e) 1.7 Hz (b) 0.90 Hz                          (d) 1.3 Hz

 

  

6. What is the difference in phase between the points A and B? 
   1. (π/4) radians                                 (c) π?radians                              (e) 2π?radians  
   2. (π/2) radians                                 (d) (3π/4) radians

 

 

 

 

 

 

 

 

 

 

 

 

 

7. A steel wire of mass 0.400 kg and length 0.640 m supports a 102-kg block. The wire is struck exactly at its midpoint causing a small displacement. How long does it take the peak of this displacement to reach the top of the wire? (a) 2.00 x ?10 ^–3 s                  (d) 8.00 x?10  ^–3 s
   1. 4.00 x ?10 ^–3 s                 (e) 1.60 x ?10 ^–2 s
   2. 6.00 x ?10 ^–3 s

 

    9. A certain string on a piano is tuned to produce middle C (f = 261.63 Hz) by carefully        adjusting the tension in the string. For a fixed wavelength, what is the frequency when this tension is doubled?

(a) 130.08 Hz                           (c) 370.00 Hz                     (e) 523.26 Hz (b) 185.00 Hz                           (d) 446.63 Hz

  

10. A wave is traveling at 5.5 m/s on a string with a linear density of 0.082 kg/m. What is         the tension in the string?
    1. 0.20 N                  (c) 2.5 N                 (e) 6.3 N (b) 0.45 N                  (d) 4.4 N

 

 

11. A transverse periodic wave described by the expression

(where y and x are in meters and t is in seconds) is

 

established on a string. Which one of the following  statements concerning this wave is false?

 

1. 1. The wave is traveling in the negative x direction.
   2. The amplitude is 1.0 m.
   3. The frequency of the wave is 0.10 Hz.
   4. The wavelength of this wave is 2.0 m.
   5. The wave travels with speed 5.0 m/s.

 

12. A wave has an amplitude of 0.35 m, a frequency of 1.05 x10⁶ Hz, and travels in the    positive X-direction at the speed of light, 3.00 x ?10 ⁸ m/s. Which one of the following equations correctly represents this wave?

1. y = 0.35 sin (6.60 x?10  ⁶t + 0.022??                       X)               (d) y = 0.35 sin (286t + 1.05 x ?10 ⁶X)
2. y = 0.35 sin (6.60 x ?10 ⁶t + 0.022X)         (e) y = 0.35 sin (1.05 x 10? ⁶t + 3.00 x ?108 X) (c) y = 0.35 sin (286t 1.05??                    x ?10 ⁶X)  

 

13. A bell produces sound energy at a rate of 4.00 x ?10 ^–3 W and radiates it uniformly in all          directions. What is the intensity of the wave 100.0 m from the bell?

(a) 3.18 x?10  ^–8 W/m²                       (c) 5.02 x ?10 ^–2 W/m²                (e) 6.28 x ?10 ⁷ W/m² (b) 3.14 x ?10 ^–7 W/m²                       (d) 5.02 x ?10 ² W/m²

 

14.During a typical workday (eight hours), the average sound intensity arriving at  Larry’s ear is 1.8 x ?10 ^–5 W/m². If the area of Larry’s ear through which the sound passes is 2.1 x ?10 ^–3 m², what is the total energy entering each of Larry’s ears during the workday?

1. 1. 1.8 x ?10 ^–5 J                        (c) 7.4 x ?10 ^–4 J                   (e) 4.1 x ?10 ^–3 J (b) 2.2 x ?10 ^–4 J                        (d) 1.1 x ?10 ^–3 J

 

 

15.Two boys are whispering in the library. The radiated sound power from one boy’s          mouth is 1.2 x ?10 ^–9 W and it spreads out uniformly in all directions. What is the minimum distance the boys must be away from the librarian so that she will not be able to hear them? The threshold of hearing for the librarian is 1.00 x ?10 ^–12 W/m².

1. 1. 100 m                             (c) 23 m                         (e) 9.8 m (b) 35 m                               (d) 16 m 

 

 

16. The decibel level of a jackhammer is 130 dB relative to the threshold of hearing. 

Determine the decibel level if two jackhammers operate side by side.

1. 65 dB                        (c) 133 dB                   (e) 260 dB
2. 130 dB                      (d) 144 dB

 

 17. At a distance of 5.0 m from a point sound source, the sound intensity level is 110 dB. 

At what distance is the intensity level 95 dB?

1. 1. 5.0 m                        (c) 14 m                       (e) 42 m
   2. 7.1 m                        (d) 28 m

 

 18. According to US government regulations, the maximum sound intensity level in the    workplace is 90.0 dB. Within one factory, 32 identical machines produce a sound intensity level of 92.0 dB. How many machines must be removed to bring the factory into compliance with the regulation?

1. 3. 2                        12                  (e) 24
   4. 8                        16