# Equation for simple harmonic motion

1. Mar 30, 2004

### dom

i was just wondering if anybody knew where i could find the equation for simple harmonic motion (SHM). I have found loads but not the right one. i need the one that starts... y=e(^-3wnt)*Asin(wdt)+(Asin(wt)/SQRT(l-(w^2/wn^2)^2+... anyone got any ideas? got assignment to hand into uni tomorrow and i need it bad

2. Mar 30, 2004

### Chen

I never saw any equation for SHM that starts like that. The ones I know are:
$$x(t) = A\cos (\omega t + \phi)$$
$$v(t) = -A\omega \sin (\omega t + \phi)$$
$$a(t) = -A\omega ^2 \cos (\omega t + \phi)$$

3. Mar 30, 2004

### Integral

Staff Emeritus
I looks to me like you have a specific solution to a specific problem. It appears to be a case of damped ossiliations, but in no way is it an equation that you will find on the web. If you could post the specifics of the problem it is a solution to we may be able to help you. We need the original DE and the initial conditions.

4. Mar 30, 2004

### dom

its an equasion for the vibration of a ball on a spring, i am comparing my excel model to the one i made on a program called working drawing.

5. Mar 30, 2004

### Integral

Staff Emeritus
The equation you posted is the solution to a Differential Equation with initial values. Without this information, I do not see how we can reproduce the solution. What are the initial conditions, what is the damping function. (your solution is damped) Is there a driving function? Without these details we cannot reproduce the solution.

Last edited: Mar 30, 2004