Answer:
Explanation:
Let the hails are coming down with speed "v" and then rebound with the same speed in opposite direction
So here the change in the momentum of the hails is given as
now we know by Newton's 2nd Law
here we have
now plug in all data
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: