1. Wave Properties
Chapter 14

2. Types of Mechanical Waves
Longitudinal Waves
Transverse Waves

3. Mechanical Waves
Wave pulse= a single bump or disturbance that travels through a medium
Periodic Wave= a wave that moves up and down at the same rate
Transverse Wave =a wave that vibrates perpendicular to the direction of the wave’s motion
Disturbed in the vertical direction, but the pulse travels horizontally

4. Mechanical Waves
Longitudinal Wave= the disturbance is in the same direction as, or parallel to, the direction of the wave’s motion
Surface Wave= a wave that has characteristics of both transverse and longitudinal waves

5. Measuring Waves
Longitudinal Wave

6. Measuring Waves
Transverse Wave

7. Measuring Waves
Speed= displacement of the wave peak divided by the time internal
Trough= lowest point
Crest=highest point
Wavelength (λ)= the shortest distance between points where the wave pattern repeats (crest to crest OR trough to trough)
Amplitude (A) = the maximum displacement of the wave from its position of rest, or equilibrium
Depends on how it is generated but NOT its speed

8. Measuring Waves
Phase= any two points on a wave that are one or more whole wavelengths apart are in phase
Period (T)=the amount of time required for an object to repeat one complete cycle of motion
Frequency (f)= the number of complete oscillations that a wave makes each second, measured in Hertz (Hz)

9. EQUATIONS!!!!! Frequency of a Wave: Wavelength : λ=v/f f=1/T
Frequency is equal to the reciprocal of the period
Measured in Hertz (Hz)
Wavelength : λ=v/f
Wavelength is equal to the velocity divided by the frequency
Measured in meters (m)

10. Practice Problem
A sound wave has a frequency of 192 Hz and travels the length of a football field, 91.4m, in s.
What is the speed of the wave?
What is the wavelength of the wave?
What is the period of the wave?
If the frequency was changed to 442 Hz, what would be the new wavelength and period?
ANS:
v=337m/s
λ= 1.76m
T= s

11. Wave Behavior

12. Waves at Boundaries
Speed of a mechanical wave depends only on the properties of the medium it passes through
What would happen when a wave passes from one medium to another?
Pulse from the wave in the first medium continues into the new medium at the specific speed
Incident wave= a wave that strikes the boundary between mediums
Reflected wave= the returning wave
Phet

13. Superposition of Waves
Principle of superposition= the displacement caused by two or more waves is the algebraic sum of the displacements caused by the individual waves
Translation= two or more waves can combine to form a new wave
Interference= the result of the superposition of two or more waves

14. Interference
Constructive Interference= When the crest of one wave overlaps the crest of another their individual effects add together to produce a wave of increased amplitude
Destructive Interference= When the crest of one wave overlaps the trough of another wave their individual effects are reduced

15. Standing Wave
Standing wave= a wave that remains in a constant position
This phenomenon can occur because of constructive interference caused by
the medium is moving in the opposite direction to the wave
Or… it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions.
Animation

16. Standing Waves
A node is a point along a standing wave where the wave has minimal amplitude
An antinode is a point where the amplitude of the standing wave is a maximum
These occur midway between the nodes.