riving you along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind and you perceive the frequency as 1370 Hz. You are relieved that he is in pursuit of a different speeder when he continues past you, but now you perceive the frequency as 1330 Hz. What is the speed of the police car

The speed of the police car is 33.98 m/s

Explanation:

Given;

first speed, v₁ = 35 m/s

first frequency, f₁ = 1370 Hz

second frequency, f₂ = 1330 Hz

second speed, v₂ = ?

Speed of sound is directly proportional to its frequency;

v = fλ

assuming the λ is constant, then,

Therefore, the speed of the police car is 33.98 m/s

your answer is c! hope this : )

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s