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:
18.9 <em>N or </em><em>19</em><em> N </em>rounded
Explanation:
m = 0.145 kg
a = 130 m/s^2
F = ma = (0.145 kg)(130 m/s^2) = 18.9 <em>N</em>
Answer:
m is expressed in kilograms and r in metres, with I (moment of inertia) having the dimension kilogram-metre square.
You need to know the specific heat capacity of air.
Then energy needed = 0.005 x sp.heat.cap x 10