{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

12 Waves 3

# 12 Waves 3 - When two(or more waves of the same kind...

This preview shows pages 1–10. Sign up to view the full content.

When two (or more) waves of the same kind propagate through the same region, they produce a composite wave. This phenomenon is called interference . It is constructive , when the waves reinforce each other. It is destructive , when they reduce each other’s amplitude. Usually the disturbances (displacements) the waves produce are added algebraically . This is called superposition principle.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Superposition principle: adding two square waves + ?
Superposition principle: adding two harmonic waves + ?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Superposition of pulses: Constructive Interference
Superposition of pulses: Destructive Interference For a moment it the string becomes a straight line – no disturbance is seen. Does the energy of wave motion disappear? Where does it go? How can the two waves go on after that? Two kinds of energy in the wave motion: potential – depends on deflection of the string from the straight line; kinetic – depends on velocity of motion of the string. In the very moment, when the string becomes straight, it is actually moving very fast - high K .

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
http://www.kettering.edu/~drussell/Demos/superposition/superposition.html
When there are two interfering waves with close but different frequency the result of the interference is the beats . They are perceived as a wave with an average frequency , but with a slowly oscillating amplitude .

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
When there are two interfering waves with close but different frequency the result of the interference is the beats . They are perceived as a wave with an average frequency , but with a slowly oscillating amplitude . ] ) ( 2 1 cos[ ] ) ( 2 1 cos[ 2 ) ( 2 1 2 1 t t A t y ω ω ω ω + = ) cos( ) ( 1 1 t A t y ω = ) cos( ) ( 2 2 t A t y ω = ) cos( ) cos( ) ( ) ( ) ( 2 1 2 1 t A t A t y t y t y ω ω + = + = The resulting composite wave:
When there are two interfering waves with close but different frequency the result of the interference are beats.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}