How can I graph the pendulum function without knowing the constants?

AI Thread Summary
To graph the pendulum function θ(t) without knowing the constants θ₀ or r, one can focus on the general shape of the sine function. The key is to recognize that the graph will resemble a stretched sinusoidal wave, where the amplitude and zeros can be determined conceptually. For the cases of φ = 0 and φ = π/2, the sketches will differ primarily in their vertical stretch and phase shift. Understanding that θ₀ and r are constants allows for a qualitative sketch rather than a precise graph. Overall, the discussion emphasizes the ability to create a visual representation based on the function's characteristics rather than exact numerical values.
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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 don't know \theta_0 or r? I know they are both constant though, does this have a bearing on the situation?

Thankyou
 
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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.
 
thankyou...

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

I think i can do that :smile:

Thanks again
 
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