I dont understand how to do this, help please?

Question

You and a friend are sitting in the bleachers of a major league baseball park, 140 m from home plate on a day when the temperature is 20°C. Your friend is listening to the radio commentary with headphones while watching. The broadcast network has a microphone located 17 m from home plate to pick up the sound as the bat hits the ball. This sound is transferred as an EM wave a distance of 66,000 km by satellite from the ball park to the radio.

What is the shortest time interval between the bat hitting the ball and one of you hearing the sound?

How much later does the other person hear the sound?

Answer 1

Let's see, wikipedia sez speed of sound under these conditions (assuming 0% humidty & sea level) is about (331.5 + 0.6(tempC))m/sec =

331.5 + 0.6(20) =

343.5 m/sec;

That of light, 299.8(10^6)m/sec

So sitting in the bleachers, you hear the crack of the bat

140m/343.5m ~=0.408 seconds delayed.

Your friend w/ radio hears it:

[(17m/343.5m) + (66,000km/299,800km)] sec =

0.0495 + 0.2201 =

0.270 seconds delayed, which is the shortest time interval, and obviously you will hear it 0.138 seconds later, right?

Answer 2

You have to calculate several time intervals. You'll need this data:
Speed of sound at STP is 331.4 m/s
Speed of light is 3*10^5 km/s

Calculate the time interval from when the ball was hit to when you heard it without help of the radio. (hint: speed of sound)

Compare that with the sum of these time intervals (which gives you the time from when the ball was hit to when the radio headphones got the sound):
Calculate the time interval from when the ball was hit to when the microphone picked it up. (hint: speed of sound)
Calculate the time interval from the last event to when the satellite got the signal. (hint: speed of light)
Assume the signal then goes straight to your radio headphones and calculate the time interval from the last event to when the headphones pumped the sound into your ears.

Note: Gary H forgot to consider the time for the signal to come down from the satellite.

Answer 3

rent a movie on how to do it