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:

• When there is TV transmission or telecommunication, there are radio waves set up making the electric and magnetic fields vary in simple harmonic motion.

This is a TV, not a microwave

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 never-ending...

• 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!