tolong bantuannya ya...

Efek doppler

Dik :
Sumber mendekati pendengar => vs (-)
vs = 20 m/s
fs = 720 Hz
vp = 0 m/s
v = 340 m/s

Dit:
frekuensi pendengar (fp)
fp = [ (v + vp) / (v - vs) ] . fs
fp = [ (340 + 0) / (340 - 20)] . 720 Hz
fp = [ 340 / 320 ] . 720 Hz
fp = 765 Hz
Jawaban D

Fs = 720 Hz
Vs = 20 m/s
Vp = 0 m/s
V = 340 m/s 

Fp = (V - Vp/V - Vs) × Fs
Fp = (340 - 0/340 - 20) × 720
Fp = 340/320 × 720
Fp = 244.800/320
Fp = 765 Hz (Jawaban D. 765 Hz)