Answer:
a) The car was moving at a speed of 
b) The negative sign of 
denotes that the observer is coming towards the police car which is the source of the sound.
c) 
Explanation:
Given:
- original frequency of the source,
- speed of the source,
- velocity of the obstacle car be,
- speed of sound,
- observed frequency,
<u>Using the equation from the Doppler's effect:</u>
a)
The car was moving at a speed of
b)
The negative sign of denotes that the observer is coming towards the police car which is the source of the sound.
c)
Now when, 
Then, 
Using the Doppler's eq.:
Your answer is B. The human eye can only detect color and Tv waves
If its not Distance traveled then its energy
8500 Hz and Longitudinal
Speed = frequency x wavelength
Speed of sound at 20 degrees Celsius is approximately 340 m/s
Answer:
l= 3.002 cm
Explanation:
Given that
n= 70 turns
B= 1.2 T
θ= 15°
I= 1.5 A
τ = 0.0294 N⋅m
Lets take length of sides is l.
We know that
τ = n I A B sin θ
Area of square ,A= l²
Now by putting the value
τ = n I A B sin θ
0.0294 = 70 x 1.5 x l² x 1.2 x sin 15°
l² = 0.000901 m²
l² = 9.01 cm²
l= 3.002 cm
