1. Simple Harmonic Motion

2. Repeated Motion What are some examples of something that repeats?
What is common to all repeated things?
Time interval
Path taken
How often

3. Special Repeated Motion
Called Simple Harmonic Motion (SHM)
Two main requirements:
Repeated motion
A force that constantly returns it to equilibrium
Examples of non-SHM:
Going to school
Planets orbiting sun

4. Examples of SHM Two main ones:
Pendulum
An object swinging back and forth under the force of gravity
Spring System
An object vibrating on a spring.
We will talk in this class only about pendulums.

5. Pendulums Two important properties about SHM that we classify:
Period (T)
The TIME it takes to make one complete repetition
Measured in units of time (seconds, minutes, etc)
Frequency (f)
The NUMBER of repetitions in one second
Measured in units of Hertz. (1/seconds)
Period and frequency are inversely related
period = 1 / frequency

6. Pendulum Properties
What things DO affect the period of a pendulum? (brainstorm at table)
Length
Gravity
What things DO NOT affect the period of a pendulum? (brainstorm at table)
Mass!
Amplitude (how high you start it)

7. SHM Gives Sine Curves
If something moves in SHM, the graph of its motion is a sine curve.
We can see all the wave properties present in the sine curve.