CH+17+Notes

NOTES  media type="custom" key="3769509"

media type="custom" key="3839053" Chapter 17 Pretest/Review  What is energy? The ability to do work What is mechanical energy? True or False: Displacements in opposite directions add together How is speed calculated? What are the standard units of distance and time? Which is longer, 0.25 cm or 25 m? What happens to the spacing of the particles within a solid or liquid as the temperature increases? What happens to eh speed of the particles in a solid, liquid or gas as the temperature is increased? If a car takes 2 hrs to travel 100 km., what is its average speed?

Label the parts of a [|Transverse Wave]. media type="custom" key="726401" Nature of Waves Waves and Energy
 * [|Example 1]
 * [|Example 2]
 * Waves: A disturbance that transfers energy through matter and space.
 * Kinetic Energy is energy of motion
 * Waves through a Medium

MEDIUM: Any substance or region through which a wave is transmitted.
 * For certain waves, a medium of matter is not required, in other words it can go through a vacuum.
 * Light is an example

2 Properties of a Medium
 * Density: Inversely proportional (one increases the other decreases(speed)
 * Elasticity: the ability of a material to return quickly to its original shape after being disturbed. (Directly proportional)

 17.1 Types of Waves A. Transverse Wave : A wave in which the motion of the medium is at right angles to the direction of the wave.

Parts of a Transverse Wave

Longitudinal Wave : Compressional waves  Characteristics of Waves  Amplitude : the maximum distance the molecules are displaced from their rest position  Wavelength : The distance between two consecutive crests or troughs of a wave. [|Frequency] : The number of complete waves, or complete cycles, per unit of time. Speed of Waves  Reflection : the bouncing back of a wave after it strikes a boundary that does not absorb the wave's energy  Incident Wave : the incoming wave. <span style="color: rgb(246, 35, 35);"> Reflected Wave : the wave that is bounced back <span style="color: rgb(29, 98, 24);"> Angle of incidence : the angle formed by the incident ray and a line perpendicular line to the barrier <span style="color: rgb(232, 23, 23);"> Angle of Reflection : the angle formed by the reflected ray and a line perpendicular to the barrier <span style="color: rgb(10, 143, 22);">Refraction : The bending of [|waves] due to a change in speed <span style="color: rgb(209, 16, 16);">[|Diffraction] : The bending of waves around the edge of a barrier.
 * Compression is a space in the medium in which the molecules are crowded together
 * Rarefaction: A space in the medium in which there are fewer molecules.
 * In other words, it is the distance from the medium to the top of the crest.
 * As the amplitude increases, so does the amount of energy.
 * This symbol is lambda.
 * Usually measured in meters or centimeters.
 * For longitudinal waves, frequency is the number of compressions or rarefactions produced per unit of time.
 * The unit used to measure wave frequency is the hertz (Hz). 1 Hz - 1 wave per 1 sec
 * The [|speed of a wave] depends upon the medium in which it is traveling.
 * The speed of a wave is equal to the frequency times the wavelength.
 * Speed = frequency x wavelength
 * Occurs because waves move at different speeds in different mediums
 * Result of a new series of waves being formed when the original waves strike a barrier