An Introduction to Simple Harmonic
motion
By Abbas Tejani
What is Simple Harmonic Motion?
• Wikipedia.org defines it as:
“Simple harmonic motion is the motion of a simple
harmonic oscillator, a motion that is neither driven nor
damped.”
• All this basically means is that an oscillator oscillates
about a mid-point called the equilibrium position
How, mathematically, do we know
if a situation is SHM?
• It can only be SHM If the motion is periodic, and and
can be described as that of a sine function, with
constant amplitude.
• No… Not that type of amplitude
So what does that mean?
• This basically means that the graph looks like this
• Learn it!
Some everyday examples...
• Simple harmonic motions can come in many different
forms
• For example, a person bouncing on the end of a diving
board...
• A child in a swing...
• Or your cousin’s funky car (you know,
the one that bounces like a low-rider
every time you go over a ramp…)
How do we know that they are
SHM?
• With the diving board, the woman with a death-wish
oscillates up and down with a constant amplitude.
• The boy stuck in the tyre oscillates from side to side as
the swing moves with a constant amplitude.
• The Aston Martin V12 Vanquish’s suspension oscillates up
and down every time you go over a ramp with a
constant amplitude.
• However, in all these cases, there is damping. If we
ignore the effects of damping, we will see simple
harmonic motion that looks a bit like each of these:
How can SHM lead to the
production and transmission of
waves?
• Freemasons?
• Likely, but no. If we take an everyday example, such as
a TV:
This is a TV,
not a
microwave
•
When there is TV transmission or telecommunication,
there are radio waves set up making the electric and
magnetic fields vary in simple harmonic motion.
Electric and magnetic fields…
Haven’t I heard that somewhere?
• Correct! Simple Harmonic Motion varying between the
electric and magnetic fields in the space through which
waves travels produces...
• This slide show will not progress until someone answers
the question...
• Not going very far are we…?
• Maybe this is one of those slide shows that is neverending...
• At least until you all go insane...
• Don’t know about you, but this slide show is boring me…
So I think I’ll give you the answer...
Electromagnetic waves!
• Be it gamma rays, X rays, or microwaves, the essential
common feature is that there are simple harmonic
variations of electric and magnetic fields in the space
through which the waves travel.
Gamma ray Alien!
So what did we learn?
• We’ve learnt that Simple Harmonic Motion is not just
some mode of strange behaviour confined only to a
physics laboratory
• It fills every aspect of our lives!
• Could we live without Simple Harmonic Motion?
• Nope
Now let’s see that Aston Martin
again...
Thank you, you’ve been a great audience!