Lightning and Thunder

A flash of lightning is seen, and
the resulting thunderclap is heard 3 seconds later. If the
speed of sound averages 1100 feet per second, how far away
is the storm?

Jhun Vert's picture

Assume the light to be in absolute position. I don't know if my term is correct but what I mean is this; there is no time-gap for the flash of light to reach your location. In this thinking, the only thing that travels here is the sound. In this case, you will just use the simple formula $s = vt$ where $v$ and $t$ are given. The answer is 3,300 ft.

If you consider the speed of light which is not given but according to Google it is approximately equal to 9.836 × 108 ft/sec then you just subtract the time difference for the light to reach the eyes and for the sound to reach the ears. The equation will then be $\dfrac{s}{v_\text{sound}} - \dfrac{s}{v_\text{light}} = 3$. This solution however, is impractical in many sense for distances here on earth.

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