15. You are watching a baseball game on television that 15 being broadcast from 4500 km away. The batter hits

the ball with a loud "crack" of the bat. A microphone

is located 22 m from the batter, and you are 2.0 m from

the television set. On a day when sound travels 343 m/s

in air, what is the minimum time it takes for you to hear

the crack of the bat after the batter hits the ball?

t_total = 6.99 s

Explanation:

It asks us how long it takes to hear the sound, for this we must look for the time (t₁) it takes for the sound to reach the microphone, the time it takes for the video signal (t₂) to reach the television and the time (₃) it takes for the TV sound to reach us, so the total delay time is

         t_total = t₁ + t₂ + t₂

we look for t1, it indicates that the distance x = 22m

          v = x / t

           t = x / v

           t₁ = 22/343

           t₁ = 6.41 10-2 s

time t₂

          t₂ = 4500 103/3 108

          t₂ = 1.5 10-5 s

time t₃

          t₃ = 2/343

          t₃ = 5.83 10⁻³

Total time is

         t_total = t₁ + t₂ + t₃

         t_total = 6.41 10⁻² + ​​1.5 10⁻⁵ + 0.583 10⁻²

         t_total = 6.99 s