The speed of light is 3.0×108 m/s and the speed of sound is 3.4×102 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!
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 :
You have:
So, you say that for sound to travel 1 km, it takes 3 seconds (integer), and hence, N = 3.