Graphing pendulum function

1. Jan 23, 2005

No Name Required

Hello,

Ive done the first part of a question which was to derive the equation

$$\displaystyle{\theta(t) = \theta_0 \sin(\omega_0t + \phi)}$$

for a pendulum

where $$\displaystyle{\omega_0 = \sqrt{\frac{g}{r}}}$$ and $$\displaystyle{\phi = \sin^{-1} \left(\frac{\theta_1}{\theta_0}\right)}$$

$$r = \mbox{length of rod (pendulum)}$$

The next part says

Sketch $$\theta(t)$$ versus $$t$$ for the cases $$\phi = 0$$ and $$\displastyle{\phi = \frac{\pi}{2}}$$

How do I do this if i dont know $$\theta_0$$ or $$r$$? I know they are both constant though, does this have a bearing on the situation?

Thankyou

Last edited: Jan 23, 2005
2. Jan 23, 2005

dextercioby

1.There's a typo in the first formula.A "t" is missing in the (round) bracket...

2.The graph is basically a streched (on "y") sinusoid...So it ain't a big deal to draw it.You have to determine the amplitude,the zeros and that's it...

Daniel.

3. Jan 23, 2005

No Name Required

thankyou...

Ok, so im just basically sketching it and trying to make it look nice

I think i can do that

Thanks again