Question

While filming an intense action sequence for the next James Bond movie, a controlled explosion detonates 1.1 km away from the actors. If the speed of sound through solid rock is 3000 m/s on average, the actors will feel the explosion before they hear it. How much time will pass between when they feel the explosion and when they hear it?

Answer 1

Answer:

The time that will pass between the feeling and hearing the explosion is 2,86 secs

Explanation:

First, let's calculate the time that the wave takes to travel until the actors feel the explosion:

$1,1 km*\frac{1.000 mts}{1 km} *\frac{sec}{3.000 mts} = 0,37 secs$

Now, the time that pass while the actors hear the sound is:

(Remember that the sound speed in the air is 340 m/s on average)

$1,1 km * \frac{1.000 mts}{1 km} * \frac{sec}{340 mts} = 3,23 secs$

So, the time between the feeling and hearing is 3,23 - 0,37 = 2,86 secs