# Simple Harmonic Motion Problem

1. Mar 5, 2014

### whitehorsey

1. What is the difference between ψ = Amod(t) cos (wavt)and the simple harmonic oscillator?

3. A. The amplitude is time dependent
B. The amplitude,Amod , is twice the amplitude of the simple harmonic oscillator, A.
C. The oscillatory behavior is a function of ? instead of the period, T.

I'm not sure what the difference is. I thought that the equations are similar but that was incorrect.

2. Mar 6, 2014

### BvU

What is ψ for a simple harmonic oscillator ?

3. Mar 6, 2014

### whitehorsey

Simple harmonic oscillator:
ψ = 2A[cos(wavt) cos(1/2 wbeatt)]

Amod (t) = 2Acos(1/2 wbeatt)

In the book, it says the maximum amplitude Amod of the wave changes with time. Would that mean it is A?

4. Mar 7, 2014

### BvU

My simple harmonic oscillator $\ddot x + \omega^2 x = 0$ doesn't have a beat frequency. Only $A\cos(\omega t + \phi)$ with $A$ and $\phi$ constant.