a highway patrol officer is targeting a car that is receding from her at 65m/s.

Question

a highway patrol officer is targeting a car that is receding from her at 65m/s. the officer herself is parked. her radar gun sends out a radar wave at 34.6 GHz (1.0 GHz = 1.0x10^9 Hz).
use Vsound= c = 3.0 x 10^8 m/s.
A) what is the frequency of the radio wave returned to the radar gun?
B) what is the beat frequency of the wave generated in her gun by this signal? a highway patrol officer is targeting a car that is receding from her at 65m/s. the officer herself is parked. her radar gun sends out a radar wave at 34.6 GHz (1.0 GHz = 1.0x10^9 Hz).
use Vsound= c = 3.0 x 10^8 m/s.
A) what is the frequency of the radio wave returned to the radar gun?
B) what is the beat frequency of the wave generated in her gun by this signal? a highway patrol officer is targeting a car that is receding from her at 65m/s. the officer herself is parked. her radar gun sends out a radar wave at 34.6 GHz (1.0 GHz = 1.0x10^9 Hz).
use Vsound= c = 3.0 x 10^8 m/s.
A) what is the frequency of the radio wave returned to the radar gun?
B) what is the beat frequency of the wave generated in her gun by this signal?

Explanation / Answer

f ( frequency of radar gun) = 34.6*109 hz

let f' is the apprent frequency of radar wave received by car.

f' = ( 1+ V/c) * f

car reflects the radar wave of apprent frequency f' towards the radar gun.

if f'' is apprent frequency detected by radar:

f'' = ( 1+ V /c) f'

   = ( 1+ V/c) * ( 1+ V/c) * f

   = ( 1+ V/c)2 * f

here V/c is very small so expanding it binomally and neglecting higher power of V/c.

f'' = ( 1+2V/c) * f

   = ( 1+ 2* 65 / 3*108 ) * 34.6*109

   = 3.46*1010 hz

this is the frequency returned to gun.

b) beat frequency = f-f"

   = 34.6*109 - 3.46*1010

   = 0 hz

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.