What is the difference between harmonic and nonharmonic motion?

[deadlytrogdor]

I feel like I should know this but I'm not sure that I do...

What is the difference between harmonic and nonharmonic motion? I did a quick google of this, but I didn't find it helpful...

The most helpful thing I read was that harmonic motion can be reduced to a sine or cosine function. Is that correct?

 

[technician]

Use the word 'oscillations'.
All types of oscillations need to be analysed... agreed?
The 'simplest' ,in mathematical terms, are Simple Harmonic oscillations or SHM
What makes them 'simple' is the condition that restoring force is proportional to displacement.
ie F =-kx, or acceleration a = -(k/m)x
You know that a = dv/dt and v = dx/dt so this motion can be derived from motion where x=Acos(ωt), so v = -ωASin(ωt) and a = -ω^2(Cosωt)