LO3 for PHYS 101

1. Harmonic Waves:
An Introduction
Jasmine Keller 27756148 LO3

2. Understanding a Graph: sin(x)
Crest:
maximum displacement
Trough:
minimum displacement
Wavelength λ
amplitude
nodes

3. Changing the Amplitude
Lower Amplitude
Higher Amplitude
Amplitude has a dimension
of length and is always positive

4. Changing the Frequency
Lower Frequency
Higher Frequency

5.  ν=λf
 Using k=2π/λ and f=ω/2π, we can write the wave
speed in terms of angular frequency of a harmonic
wave
 v= λf=(2π/k)(ω/2π)=ω/k
Wave Speed Relationships
k represents the wave number. We can determine the relationship between k
and λ by the fact that waveform repeats over length λ such that:
D(x)=D(x+λ)
And applying this to D(x)=Asin(kx) gives
k= 2π/λ

6.  Two waves on identical strings have frequencies in a
ratio of 2:1. If their wave speeds are the same, how do
their wavelengths compare?
 a. 2:1
 b. 1:2
 c. 4:1
 d. 1:4
Example: wave speed and wavelength
Source: http://www.physicsclassroom.com/class/waves/Lesson-2/The-Wave-Equation

7.  Two waves on identical strings have frequencies in a
ratio of 2:1. If their wave speeds are the same, how do
their wavelengths compare?
 a. 2:1
 b. 1:2
 c. 4:1
 d. 1:4
Example: wave speed and wavelength
Source: http://www.physicsclassroom.com/class/waves/Lesson-2/The-Wave-Equation
Frequency and wavelength are inversely
proportional to each other. The wave with the
greatest frequency has the shortest
wavelength. Twice the frequency means one-
half the wavelength. For this reason, the
wavelength ratio is the inverse of the frequency
ratio.