1
VIBRATIONS AND
WAVES
Chapter 13
VIBRATIONS AND WAVES
circle6
Waves carry (propagate) energy
circle6
Waves on a string
circle6
Light waves
circle6
Waves are related to oscillations
circle6
So we begin by looking first at simple oscillatory
motion
Simple Harmonic Motion (I)
circle6
Specific type of periodic motion
circle6
Simple Harmonic Motion (SHM)
circle6
Due to Hooke’s law.
F
s
=  kx
circle6
x = displacement from equilibrium
circle6
k is the spring constant. (Determined by the stiffness of the spring)
circle6
The further away the system is from equilibrium, the stronger the
force F
s
=  k x
circle6
Resulting motion is described by a sine or cosine curve i.e.
harmonic functions
circle6
SHM is periodic, but there are periodic motions that are not SHM
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
2
Simple Harmonic Motion (II)
circle6
x = 0 is
equilibrium position
circle6
Pull the mass to
maximum
amplitude
x = A
circle6
With no friction present, the mass
will continue to oscillate between x
=
±
A
circle6
Period
of oscillation is T
circle6
Frequency
of oscillation is
f = 1/T
circle6
Units are: Hz = cycles/sec
Newton’ 2
nd
Law and SHM
circle6
From Newton’s second law we have:
F =  kx = ma
circle6
Therefore
a =  kx / m
circle6
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 JamesR.Boyd
 Energy, Simple Harmonic Motion, Light, Transverse waves

Click to edit the document details