# Vibration and Waves

posted by
**Sam**
.

1. A girl on a playground swing makes a complete to-and-fro swing each 2 seconds. The frequency of swing is

1. (0.5 hertz)

2. (1hertz) (ANSWER)

3. (2 hertz)

And the period is (FROM THE QUESTION BEFORE)

1. (0.5 seconds) (ANSWER)

2. (1 second)

3. (2 seconds)

2. The period of a 444-hertz sound wave is _____ second(s).

ANSWER: 220

3. A marine weather station reports waves along the shore that are 8 seconds apart. The frequency of the waves is therefore _____ hertz.

ANSWER: 16

4. The annoying sound from a mosquito occurs because it beats its wings at the average rate of 600 wingbeats per second.

( a.) What is the frequency of the soundwaves?

ANSWER: 600 vibrations per second.

( b.) What is the wavelength? (Assume the speed of sound is 340 m/s.)

ANSWER: 0.57 (rounded) meters

5. When an automobile moves towards a listener, the sound of its horn seems relatively _____

1. High pitched (ANSWER)

2. Low pitched

3. Normal

When moving away from the listener, its horn seems ______

1. High pitched

2. Low pitched (ANSWER)

3. Normal

6. The changed pitch of the Doppler Effect is due t changes in_______

1. Wave Speed

2. Wave Frequency (ANSWER)

Thanks so much for the help!!