Kater's Pendulum ```Name: Lyndsey K. Status: student Age: 17 Location: N/A Country: N/A Date: 2/18/2004 ``` Question: I have been trying to prove gravity using only the period of a pendulum. I have tried any possible way, and I still cannot do it. How do you solve for gravity using only the period of a pendulum? Replies: Dear Lyndsey, I am not sure what you mean by "prove" gravity. "Prove" its existence as a force, or prove that the measured value is 9.8 m/s2? If it is indeed the latter, I can think of two ways. E-mail me again and explain what you have done so far. If I can see how you have approached the problem; I can probably point you in the right direction. If you are talking about messing with equations; you probably have something like this already: p stands for pi. My symbol does not seem to transfer to e-mail T is approximately = 2p X the square root of the quantity ( I/ mgh) where I is = mL2. You can substitute the mL2 for the I, giving you ( mL2/ mgL) under the radical sign. This in turn can be reduced to T is approx.= 2p X the square root of (L/g). If you square everything to get rid of the radical sign, it looks big and hairy like this: T2 is approximately = 4p2 L/g This approximately = to business can be equal as long as the pendulum does not have a big amplitude. Rearrange and solve for g g= 4p2 L/T2 E-mail me back if this does not make sense. I will try sending an attachment next time. Martha Croll Click here to return to the Physics Archives

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