http://www.ck12.org Chapter 11. Wave Motion and Sound
Questionb: T=?[s]
Given: f= 0. 21 Hz
Equation: T=^1 f
Plug n’ Chug: T=^1 f= 0. 211 Hz= 4. 76 s
Answer:4 .76 sExample 2MEDIA
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- Bored in class, you start tapping your finger on the table. Your friend, sitting right next to you also starts
 tapping away. But while you are tapping once every second, you’re friend taps twice for every one tap of
 yours.
 a. What is the Period and frequency of your tapping?
 b. What is the Period and frequency of your friend’s tapping?
 c. Your tapping starts small waves going down the desk. Sort of like hitting a bell with a hammer. The
 frequency of the sound you hear is 1200 Hz. You know the wave speed in wood is about 3600 m/s. Find
 the wavelengths generated by your tapping.
- You’re sitting on Ocean Beach in San Francisco one fine afternoon and you notice that the waves are crashing
 on the beach about 6 times every minute.
 a. Calculate the frequency and period of the waves.
 b. You estimate that it takes 1 wave about 4 seconds to travel from a surfer 30 m off shore to the beach.
 Calculate the velocity and average wavelengths of the wave.
- The Sun tends to have dark, Earth-sized spots on its surface due to kinks in its magnetic field. The number of
 visible spots varies over the course of years. Use the graph of the sunspot cycle below to answer the following
 questions. (Note that this is real data from our sun, so it doesn’t look like aperfectsine wave. What you need
 to do is estimate thebestsine wave that fits this data.)
