Explanation :
As the ambulance got closer, Marge noticed that the pitch of the siren got higher. This is due to the Doppler's effect.
The siren of the ambulance has a higher pitch when it approaches Marge. When the waves move away from him, it will have a lower pitch.
As the waves come closer to us, the waves become compressed and hence the frequency of the wave increases.
Answer:
7.83
Explanation:
Just using the speed ,distance and time relation..Let time be T
Use this formula and find the distance covered by automobile .
Do same for car ..
and at last subtract the distance of automobile to car =141.
i.e (Distance of automobile -Dist.of car )=141
The answers is acceleration.
Answer:
V = 6.65 [volt]
Explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
![P=E/t\\P = 40/30\\P = 1.33[s]](https://tex.z-dn.net/?f=P%3DE%2Ft%5C%5CP%20%3D%2040%2F30%5C%5CP%20%3D%201.33%5Bs%5D)
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.

where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
![V = 1.33/0.2\\V = 6.65 [volt]](https://tex.z-dn.net/?f=V%20%3D%201.33%2F0.2%5C%5CV%20%3D%206.65%20%5Bvolt%5D)