Another Measurement of Speed of Light

AI Thread Summary
The discussion revolves around an experiment measuring the speed of light using Fizeau's apparatus, where the calculated speed was 2.889 x 10^8 m/s. The user attempted to calculate the minimum angular speed of the wheel but expressed uncertainty about their calculations. They initially derived a time of 7.638 x 10^-5 seconds but received feedback indicating a mistake in the angular displacement calculation. The correct angular displacement should be 1/720 revolutions, not 1/440, which would lead to the accurate angular speed. Clarification on the angular displacement is essential for correcting the calculations.
clairez93
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Homework Statement



In an experiment to measure the speed of light using the apparatus of Fizeau, the distance between light source and mirror was 11.45 km and the wheel had 720 notches. The experimentally determined value of c was 2.889 x 10^8 m/s. Calculate the minimum angular speed of the wheel for this experiment.

Homework Equations



c = 2d/t
t = theta/w

The Attempt at a Solution



2.998 x 10^8 m/s = 2(11450m) / t
t = 7.638 x 10^-5 s

7.368 x 10^-5 = (1/440 rev) / w
w = 9.091 rev/s
9.091 * 2pi = 57.12 rad/s

Book answer: 114 rad/s
 
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Sorry about the earlier empty message; I hit enter too early. I am not sure what mistake I have mdae in my calculations, and if someone could look it over and help me, it would be greatly appreciated.
 
clairez93 said:
7.368 x 10^-5 = (1/440 rev) / w

Why is \theta equal to 1/1440 rev (I think that's what you meant). If there are 720 notches, then \theta=1/720 rev. That will give you the right answer.
 

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