Answer:
a) The velocity of the car is 7.02 m/s and the car is approaching to the police car as the frequency of the police car is increasing.
b) The frequency is 1404.08 Hz
Explanation:
If the police car is a stationary source, the frequency is:
(eq. 1)
fs = frequency of police car = 1200 Hz
fa = frequency of moving car as listener
v = speed of sound of air
vc = speed of moving car
If the police car is a stationary observer, the frequency is:
(eq. 2)
Now,
fL = frequecy police car receives
fs = frequency police car as observer
a) The velocity of car is from eq. 2:

b) Substitute eq. 1 in eq. 2:

Answer:
C
Explanation:
According to Newton's first law of motion, which states that a body will continue in its state of rest or uniform motion unless acted upon by an external force to change its state of rest or uniform motion. So, the Voyagers spacecraft will continue to move in the same way at the constant speed of 50,000 mph unless acted upon by a force.
Electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as an output. It was discovered that the above flow of electric charges could be induced by moving an electrical conductor such as a wire that contains electric charges in a magnetic field
The answer would be D hope it helps and sorry if it is wrong. :)
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