In the movie "Taken 2", Liam Neeson is being held captive in a warehouse. He manages to call his daughter and have her retrieve some materials from his case. He has her throw a grenade from his hotel window onto a parking structure so he can hear the blast. He counts the seconds, and the blast comes approximately 4 seconds after he hears it on his cell phone. He has her take a map and draw a circle 4.5 kilometers from the hotel, and another circle 4.5 kilometers from the center of the Istanbul market, and see if they overlap.
The speed of sound is 1236 kilometers per hour, or .34 kilometers per second. If he counted 4 seconds, that would be 1.36 kilometers. Why would he have her draw circles with radii of 4.5 kilometers?
