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:

Johannes Kepler was a main stargazer of the Scientific Revolution known for detailing the Laws of Planetary Motion. A stargazer, obviously, is a man who contemplates the sun, stars, planets and different parts of room. Kepler was German and lived in the vicinity of 1571 and 1630.
Despite the fact that Kepler is best known for characterizing laws in regards to planetary movement, he made a few other striking commitments to science. He was the first to discover that refraction drives vision in the eye and that utilizing two eyes empowers profundity recognition.
A persons or animals nature, especially as it permanently affects their behavior
Same speed, because mass is neglected. The things that affect the speed are the distance and speed of the rock.