Physics 2 Chapter 16

Superposition

• interference

• how waves mix together

wave

distance in space

• carries energy

interference

the phenomenon where two or more overlapping waves meet and combine to form a new, resulting wave

• same waves and frequency

constructive interference

waves add up and build on each other

• louder

deconstructive interference

waves cancel out each because they destroy each other

• ex. noise cancelling headphones

• waves in opposite direction

Standing Waves

waves trapped between 2 boundaries

• ex. guitar, wind instrument

• don’t travel like normal waves

wavelength

equal to the distance between barriers in standing waves

node

cancelling out on both sides

fixed end vs free end of standing wave

frequency of a string increases if you

tighten it

as frequency decreases,

length of string increases

as density increases

note/µ decreases

compression

high pressure/soundwaves

rarefactions

lower pressure

open-open tube

air open

• ex. guitar

closed-closed tube

wave can be antinode

closed-open tube

• ex. trumpet, clarinet, saxophone

• lower notes

circle wave

sound goes out in all directions

beats

occur when 2 frequencies/sound waves are close to each other

length for standing waves

the same for all regardless of n (ex.n=1,2,3)

frequency increases as number of standing waves

increase (f proportional to n value)

F₁ =

first harmonic (fundamental frequency)

F₂, F₃, and anything beyond is known as

overtones

n =

number of standing waves

as n increases

wavelength decreases and frequency increases

amplitude at node

zero

constructive interference happens at

antinode

deconstructive interference happens at

node

velocity is always

constant (the same value)