00:01
In this problem on the topic of waves, we are told that two spectators are watching a soccer game, and they see a ball being kicked and hear the sound a few moments later.
00:11
The time delay for spectator a, 0 .23 seconds, and spectator b observes a time delay of 0 .12 seconds.
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Now, sightlines from the two spectators to the player kicking the ball meet an angle of 90 degrees, and we want to know how far spectator a and spectator b are from the player, and how far the two spectators are from each other.
00:33
Now, the time for sound to travel from the kicker to the spectator is d over v, where d is the distance and v is the speed of sound.
00:41
The time for light to travel the same distance is given by d over c, where c is speed of light.
00:47
And the time delay between seeing and hearing the kick is delta t, and delta t is d over v minus d over c.
01:01
Now the speed of light is so much greater than the speed of sound that the delay can be approximated by d over v.
01:11
So this means that the distance d is v delta t...