Answer:
Explanation:
We shall apply Doppler's effect to solve the problem .
Formula for apparent frequency for a source of sound approaching an observer is as follows .
f₁ = f₀ V / (V - v )
where f₁ and f₀ are apparent and real frequency of source , V and v is velocity of sound and velocity of approaching source respectively .
Putting the given values and knowing that speed of sound is 340 m /s
f₁ =346x 340 / (340 - 39.6 )
f₁ = 391.6 Hz
In case of receding train , the formula is
f₂ = f₀ V / (V + v )
Putting the values
f₂ = 346x 340 / (340 + 39.6 )
= 309.9 Hz
Change in frequency = 391.6 - 309.9
= 81.7 Hz .
Answer:
initial velocity =starting velocity
final velocity=last velocity
keep in mind the fact that velocity is a vector quantity it also has a direction
Distance covered is given as follows
1). 7 km North
2). 5 km North
3). 1 km East
Now total distance covered will be given as
Now in order to find the displacement we will show all with their directions
towards North
towards East
So total displacement is
so net displacement will be
so displacement is 12.04 km