ch 8 waves

wave velocity

v = wavelength*frequency = wavelength/period

transverse wave definition

particles in medium perpendicular to direction of waves

longitudinal wave

particles in medium parallel to direction of waves

sound waves. Longitudinal or transverse?

longitudinal

light waves. Longitudinal or transverse?

transverse

ultrasound waves. Longitudinal or transverse?

longitudinal

what are constructive inference? how is the phase difference?

additive waves, phase difference is even multiple of pi

what are destructive inference? how is the phase difference?

cancel each other/reduce amplitude, phase difference is odd multiple of pi

what is standing wave? what is the resulting wave?

two waves of same amplitude and wavelength travel in opposite directions. they cancel each other out or reinforce.

what are nodes?

no displacement due to destructive inferefernce

what are antinodes?

maximum displacement at constructive interference

speed of wave in a string

v = sqrt(T/tau) = sqrt(T/(m/L))

T = string tension

speed of sound

V = 331 + 0.61T

loudness/intensity formula

I = P/A

A = pi*r² (area of sphere)

term for above audible range

ultrasonic

term for below audible range

infrasonic

sound intensity formula

β = 10 log_10*(I/I_0)

I_0 = 1e-12

Doppler effect

f = v/wavelength

observed frequency of osund

f_0 = f_s * [(V + V_0)/(V + V_s)]

source moving away from stationary observer

f_0 = f_s * [(V)/(V + V_s)]

source moving towards stationary observer

f_0 = f_s * [(V)/(V - V_s)]

observer moving away from stationary source

f_0 = f_s * [(V + V_0)/(V)]

observer moving towards stationary source

f_0 = f_s * [(V - V_0)/(V)]

string attached at both ends: wavelength

wavelength = 2L/n

string attached at both ends: frequency

frequency = nv/2L

frequency of nth harmonic

f_n = n*f_1

pipe open at both ends: wavelength

wavelength = 2L/n

pipe open at both ends: frequency

frequency = nv/2L

a pipe open at one end: wavelength

wavelength = 4L/n

a pipe open at one end: frequency

frequency = nv/4L

wave equation for distance

y(x,t) = A sin (kx - wt + phase)

wave equation for velocity

v(t) = -Aw sin (wt + phase)

first harmonic/fundamental frequency is at n = ?

n = 1

first overtone is at n = ?

n = 2 for string attached on both ends and a pipe that open at both ends

n = 3 for a pipe that open at one end

beat frequency

f_beat = | f_2 - f_1 |