Answer:
fo = 378.52Hz
Explanation:
Using Doppler effect formula:

where
f' = 392 Hz
C = 340m/s
Vb = 20m/s
Va = 31m/s
Replacing these values and solving for fo:
fo = 378.52Hz
Answer:
The speed of the car, v = 19.997 m/s
Explanation:
Given,
The centripetal acceleration of the car, a = 13.33 m/s²
The radius of the curve, r = 30 m
The centripetal force acting on the car is given by the formula
F = mv²/r
Where v²/r is the acceleration component of the force
a = v²/r
Substituting the values in the above equation
13.33 = v²/30
v² = 13.33 x 30
v² = 399.9
v = 19.997 m/s
Hence, the speed of the car, v = 19.997 m/s