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Math Help - [SOLVED] speed of light and sound problem

  1. #1
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    [SOLVED] speed of light and sound problem

    The speed of light is 3.0108 m/s and the speed of sound is 3.4102 m/s. Find the value of the integer N in the following statement: If you start counting seconds when you see something happen and stop when you hear it happen, then the event is about 1km away for every N seconds counted.

    I'm a little confused on how to work this. I think that I should start by converting m/s into km/s, but after that I've got nothing! Thanks in advance!
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by clockworks204 View Post
    The speed of light is 3.010^8 m/s and the speed of sound is 3.410^2 m/s. Find the value of the integer N in the following statement: If you start counting seconds when you see something happen and stop when you hear it happen, then the event is about 1km away for every N seconds counted.

    I'm a little confused on how to work this. I think that I should start by converting m/s into km/s, but after that I've got nothing! Thanks in advance!
    Hi clockworks204,

    Sound travels about 1 km in 3 seconds. (3 times 3.4^2 = 1029)

    So, N = 3.
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  3. #3
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    Soo much easier than I made it out to be. Thank you!
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  4. #4
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    Since light travels very fast (the fastest 'thing' known to now), we can say that you see something instantaneously. Then, you only consider the speed of sound.

    Use the formula :

    Distance = Speed \times Time

    You have:

     1000 m = 3.4 \times10^2 t

     t = 2.94 s

    So, you say that for sound to travel 1 km, it takes 3 seconds (integer), and hence, N = 3.
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  5. #5
    MHF Contributor Unknown008's Avatar
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    Sorry, duplicate post... If a mod could delete that, it would be nice.
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