1. Explain How Banging a Tuning Fork Creates Sound Waves

AP Waves and Resonance

1. Explain how banging a tuning fork creates sound waves.

2. Why do shorter tuning forks emit sound waves at higher frequencies?

3. When using resonance to shatter a wine glass, simply providing the fundamental frequency is enough to cause the glass to vibrate, but not shatter. Why does turning up the volume cause it to shatter? Explain what’s physically happening to the glass as the volume increases.

4. How does pressing the keys on a trumpet change the available musical notes you can play?

5. Wave 1 has an amplitude of 2 meters and a frequency of 1 Hz. Wave 2 has an amplitude of 2.5 meter and a frequency of 2 Hz. Assuming the graph represents two seconds of time, draw each wave and then draw the superimposed wave. 6. How many beats would you hear from the superimposed wave in problem 9 over the course of an hour? (2 pts)

Fill in the missing frequencies

Notes 1 2 3 4 5 B 62 248 310 A 110 220 275 G 49 F 220 E 41 82 D 74 111 C 33 66 99

7. Imagine blowing a trombone without moving the slide out. Standing waves are produced by the vibration of your lips that resonate inside the trombone. However, only multiples of 1/2λ “fit” in the confined space so only certain frequencies can be played. Assuming that the “space” inside the trombone is 1.2 meters long, which frequencies can be played? (speed of sound in air is 340 m/s). How do you hit the higher notes without moving the slide? If you move the slide 0.35 meters, what are the frequencies that can be played now? (hint: how does that affect the amount of confined space?) What are octaves? (look it up!) (note: technically the trombone is an “double open-ended” instrument so the formula we’re using is a rough approximation)

8. A square sound chamber is created with sides of 50 cm. Like all musical instruments, only multiples of 1/2λ wavelengths are allowed to resonate and therefore produce notes. So, this particular chamber can only produce certain frequencies of sound. In the first three boxes, show the 2nd, 3rd , and the 6th harmonic frequencies. Sound travels at 340 m/s. Derive an equation that represents ALL the possible frequencies of notes this chamber can produce.