Answer:
The pitch that he hears after the truck passes and is moving away is 819.6 Hz.
Explanation:
The pitch that he hears after the truck passes and is moving away can be calculated using the following equation:

Where:
: is the perceived frequency
: is the emitted frequency
: is the speed of sound = 340 m/s
: is the speed of the observer = 0 (he is not moving)
: is the speed of the fire truck
First, we need to find the speed of the fire truck. When it approaches the observer we have:




Hence, the speed of the fire truck is 25.05 m/s.
Now, we can calculate the pitch that the observer hears after the truck passes:



Therefore, the pitch that he hears after the truck passes and is moving away is 819.6 Hz.
I hope it helps you!
Answer:
Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields.
Explanation:
<span> answer as followed 240km/4h=60km/h </span>
Answer:
because on an interstate or freeway, the car is cruising at a constant speed, without speeding up, slowing down, stopping, or turning constantly. In a city, cars constantly have to stop, slow down, speed up, which burns more gas in a shorter period of time
Explanation: