Vibration and Waves Worksheet

1. Known that a spring-mass system has
Vibration  = 20 times/s
Frequency= ?
                 = n  = 20 = 20 Hz
                     t       1
Period       = ?
                 = 1  = 1 seconds = 0.05 seconds
                     f    20

2. Known that a period of a pendulum is 0.40 seconds
a) Find the frequency
Frequency= 1  =   1     = 2.5 Hz
                    T     0.40
b) Times passing the lowest point in 1 second
= 2.5 times = 5 times (1 vibration will touch the lowest point 2 times)
c) Times passing lowest point in 7 seconds
= 5 x 7 = 35 times

3. Known that...
- 10 vibrations in 6 seconds
- amplitude = 4 cm
a) Find the frequency and period
F = n  = 10  = 1.67 Hz
       t       6
P = 1  =   1   = 0.15 s
       f     1.67
b) The amplitude is 4 cm. Find the period and frequency.
- Same answers as in 3(a) -

4. Known that there are 25 oscillations/50s. Find the frequency and period.
F = n  = 25  = 0.5 Hz
       t      50
P = 1  = 1   = 2 seconds
       f     0.5

5. Known that the distance is 0.40 m and the object vibrates 25 times/min.
a) Find the amplitude
= 0.40 m  = 0.2 m
       2
b) Find the frequency
= n  = 25  = 0.417 Hz
    t      60
c) Find the period
= 1  =     1     = 2.4 s
    f      0.417
d) Find the amplitude if it is 2 meters
= 2 m  = 1 m
     2

6. Known that the frequency of an object is 260 Hz and the wavelength is 1.5 m. Find the velocity of that object.
= wavelength x frequency = 1.5 m x 260 Hz = 390 m/s

                                                                                   -8                                                    9
7. Known that the wavelength of an object is 6 x 10  m and the speed is 4 x 10  m/s
Find the period and frequency.       9                         17
Frequency =   velocity    =  4   x 10  = 0.67 x 10
                     wavelength    6       10-8
Period =  1  =      1         17 = 1.5 seconds
                f       0.67 x 10
                                                                       
8. Known that the velocity of an object is 12 m/s and the frequency is 2 Hz. Find the wavelength.
velocity = wavelength x frequency
wavelength=   velocity    = 12  = 6 m
                      frequency       2