1. What is a wave?
A wave is simply a movement of energy that travels through a medium…

2. Types of Waves
Slide 15-8 2

3. How to graph a wave?

7. Do U get it? Assume V ~ constant 1) Quiet sound, low frequency:
2) Quiet sound, high frequency:
3) Loud sound, low frequency:
4) Loud sound, high frequency:

8. Main Waves Types: Transverse
Transverse waves are when the displacement is at right angles to the direction of the wave…
Displacement
Direction
Examples include waves in water, strings, earthquakes…

10. 23/11/2018

11. Longitudinal waves
Displacement
Longitudinal waves are when the displacement is parallel to the direction of the wave…
Direction

12. Compare a longitudinal wave in a slinky to a sound wave in a tube:

13. A = pressure amplitude = max. change in pressure
very small for common sounds ( 3x10-2 Pa)
Loudness is related to pressure amplitude

14. Frequency (Pitch) of Sound Waves: number of cycles per second
Healthy young ears can hear frequencies between:
20 Hz
20,000 Hz
Infrasonic
Which end do we lose with age?
Ultrasonic
Pure tone – a single frequency sound
(most sounds are composed of many frequencies)

15. Sound can travel through any kind of matter, but not through a vacuum.
The speed of sound is different in different materials; in general, it is slowest in gases, faster in liquids, and fastest in solids.
The speed of sound is different in different materials; in general, it is slowest in gases, faster in liquids, and fastest in solids.
The speed depends somewhat on temperature, especially for gases.
The speed depends somewhat on temperature, especially for gases.

16. SOUND WAVES
Sound is a longitudinal wave produced by a vibration that travels away from the source through solids, liquids, or gases, but not through a vacuum. The speed of sound is independent of the pressure, frequency, and wavelength of the sound. However, the speed of sound in a gas is proportional to the temperature T. The following equation is useful in determining the speed of sound in air
v = T Units: m/s
Where 331 is the speed of sound in m/s at 0°C, and T is the temperature in °C

17. Which of the following increases when a sound becomes louder?
A) frequency
B) wavelength
C) amplitude
D) period
E) velocity

18. Which of the following increases when a sound becomes higher in pitch?
A) frequency
B) wavelength
C) amplitude
D) period
E) velocity

19. Characteristics of a Wave
On this wave, the wavelength and amplitude (in that order) are represented as segments
A. BD and HC
BD and IC
CE and IC
CG and HC
None of these

20. Period vs Frequency
If a spring oscillates up and down 8 times in 2 seconds, what is the period?
0.25 s
2 s
4 s
8 s
16 s
Follow-up: What is the frequency?

21. Period vs Frequency
If a pendulum oscillates back and forth 4 times in 12 seconds, what is the frequency?
0.33 Hz
3 Hz
4 Hz
12 Hz
48 Hz
Follow-up: What is the period?

22. Speed of a Wave
Waves in the ocean measure about 5m apart, and about 1.5m tall. They crash on the shore once every 2.5 seconds. What is the approximate speed of these ocean waves?
0.6 m/s
2 m/s
2.6 m/s
3.75 m/s
12.5 m/s 5m
1.5m

23. Speed of a Wave
A sound wave with a wavelength 0.725m, a period of 5 × 10-4 s, and a frequency of 2,000 Hz traveling through water can go 4.35 km in 3 seconds. What is the speed of the sound wave.
3.625 × 10-4 m/s
1.45 m/s
0.24 m/s
8700 m/s
None of these

24. The time to make 1 cycle, is also the time it takes the wave to travel 1 λ.

26. Part 1?