1. Chapter 14 ”Vibrations and Waves"
Glencoe Physics
Chapter 14
”Vibrations and Waves"

2. 14.2 Properties of Waves
There are only two methods of transferring energy between two points. One involves the transfer of matter and the other involves wave motion. Classify the following methods of energy transfer.
1. driving a nail with a hammer
2. light energy from the sun

3. Types of Waves
1. mechanical wave - a wave which propagates through matter
Example: sound
2. electromagnetic wave - a wave which can propagate through a vacuum
Example: light

4. Classification of Waves
1. longitudinal wave - a wave in which particles vibrate parallel to the direction of propagation
Examples: sound, slinky
2. transverse wave - a wave in which particles vibrate perpendicular to the direction of propagation
Examples: light, water waves

5. Wave Characteristics
1. wavelength - the distance between corresponding points in consecutive waves in a wave train
2. frequency - the number of waves which pass a point in one second
3. pulse - a single nonrepeated disturbance
4. crest - a region of upward wave displacement
5. trough - a region of downward wave displacement

6. Wave Characteristics (continued)
6. axis - an imaginary line dissecting a wave
7. node - the intersection of a wave and its axis
8. antinode - the point of maximum wave displacement
9. amplitude - (A) the maximum displacement of a wave from its equilibrium position
10. period - (T) the time required for a wave to pass a point

7. Velocity of a Wave
Velocity is defined as the time rate of change in displacement. The displacement of a wave is defined in terms of the wavelength, symbol  (the Greek letter lambda). The time required for a wavelength to pass a point is defined as the period of a wave, symbol T.
V = d / t = / T

8. Period of a Wave
The period of a wave is the time required for a complete wave to pass a point. The frequency of a wave is the number of waves which pass a point in one second. So the relationship between the period and frequency of a wave may be represented by the equations;
T = 1 / f or f = 1 / T

9. Sample Problems
1. Twenty five water waves pass a point each minute. What is the frequency of the water waves?
2. If the length of the water waves in the previous problem is 10m, find the velocity of the waves.
Page 386, 15-21

10. 14.3 Wave Behavior
1. rectilinear propagation - the movement of a wave in a straight line
2. reflection - the return of a wave from the boundary of a medium
3. refraction - the bending of a wave as it changes media
4. diffraction - the bending of a wave around objects placed in its path
5. interference - the superposition of two simultaneous waves

11. The Law of Reflection
The angle of incidence is equal to the angle of reflection.
The angles are measured between the ray and an imaginary line perpendicular to the point of contact called the normal.
A light ray strikes a mirror at an angle of What is the angle between the mirror and the reflected ray?