1. Question #1
A pendulum is observed to complete 30 full cycles in 50 seconds. Determine the period and the frequency of the pendulum.

2. ANSWER
T = 1.7 s
F = .59 Hz

3. Question #2
Frieda the fly flaps its wings back and forth 150 times each second. The period of the wing flapping is _________ sec.

4. ANSWER
1 s / 150 flaps = .007 s

5. Question #3
If you wished to produce a sound with a wavelength in air equal to the length of a 5-m room, what would its frequency be? (Note: The speed of sound in room temperature is ~340 m/s.)

6. ANSWER
68 Hz

7. Question #4
You note a 2-second delay for an echo in a canyon. What is the distance to the wall of the canyon?

8. ANSWER
340 m

9. Question #5
Waves in a lake are 1.5 m in length and pass an anchored boat 0.5 s apart. What is the speed of the waves?

10. ANSWER
3 m/s

11. Question #6
A boat at anchor is rocked by waves whose crests are 28 m apart and whose speed is 7 m/s. How often do these waves reach the boat?

12. ANSWER
4 s

13. Question #7
Radio amateurs are permitted to communicate on the “10-meter band”. What frequency of radio waves corresponds to a wavelength of 10 m? (The speed of radio waves is 3.0  108 m/s.)

14. ANSWER
3 X 10^7 Hz

15. Question #8
A radio station broadcasts at a frequency of 600 kHz. Knowing that radio waves have a speed of 3.00  108 m/s, what is the wavelength of these waves?

16. ANSWER
500 m

17. Question #9
An explosion occurs 340 km away. Given that sound travels at 340 m/s, What is the time the sound takes to reach you ?

18. ANSWER
1000 s

19. 14. The string at the right is 1
14. The string at the right is 1.5 meters long and is vibrating as the first harmonic. The string vibrates up and down with 20 complete vibrational cycles in 5 seconds. Determine the frequency, period, wavelength and speed for this wave.

20. ANSWER
Wavelength = 3 m
frequency = 4 Hz
period = .25 s
Speed = 12 m/s