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speed of light in mph

Avatar Image scouse1979
20:31 on Sun 05/Mar/06

It would take a car travelling at a constant speed of 100mph, 106 years (don't worry about leap years) to reach the Sun from Earth. It takes light 8.5 minutes to make the same journey in the opposite direction.


Using the above information, what is the speed of light in mph?


If you work it out correctly, the figure you get is pretty close to the actual speed of light
in mph.

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spacechimp
(20:33 on Sun 05/Mar/06) Well, I know the speed anyway...
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spacechimp
(20:43 on Sun 05/Mar/06) Using that i seem to get something entirely wrong..
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spacechimp
(21:05 on Sun 05/Mar/06)

100x106x365x24 = 92856000 (distance in miles from earth to sun)


92856000/(8.5/60) = 655454117.6 (speed of light in mph)


and lo and behold, actual speed is 670,616,629.4. I made a mistake in my working out before.
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JudgeJ
(10:49 on Mon 06/Mar/06)

What's the question, scouse1979?


Presumably to arrive at the 106 years you knew the distance from the earth to the sun. And it seems you knew that light takes about 8.5 minutes to reach the earth from the sun. So you knew the distance and you knew the time taken by light to cover the distance. Why not simply divide one by the other? Where does the car come in to the equation???
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Cloned
(10:52 on Mon 06/Mar/06) Why do that when u can use your microwave and some cheese. to work out the speed of light. Put a bowl upside down on the rotating part of your microwave, so then when u put a plate on it the plate does not rotate. On the plate put some cheese (Make sure it is flat, if u don't like cheese use flat chocolate). Put the microwave on high and turn it on for a few seconds. You should then see two melted points or more. The distance between is then half the wavelength. Times this by the frequency of your microwave (which is written somewhere on your microwave) and you get the speed of light. Then just convert the figures and you got the speed of light in mph and some melted cheese/chocolate or even marshmellows.

Eg 2450MHz x 0.122m = 2.99 x 10^8m/s
2.99 x 10^8m/s x 2.23693629 = 668620257.1mph
6.69 x 10^8mph. Which is much closer, and without the need of a long car journey.
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Fatboy
(15:13 on Mon 06/Mar/06) Or you could just do the speed of light in Miles per second times minutes (60) times Hours (60) 186,000 x 3600 = 669,600,000 mph. Far Easier then anything else, saved yourself a lot of calculation.
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spacechimp
(18:42 on Mon 06/Mar/06) I think you all missed the point. The idea was to try and work it out using the information given, as I did.
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markja
(23:32 on Tue 07/Mar/06) scouse, was it a petrol or diesel car? maybe an electric car with a solar panel would have been a good idea. also how well did the sun roof work?

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