Doppler effect?

[Starlight]

Seems like my questions are never ending

An instrument emits an ultrasound of fq 1.500 MHZ which is reflected from a part of the heart moving away from the transducer.

Take speed of sound in body tissue as 1500 m/s, assume the part of the heart reflecting the ultrasound back tothe transducer moves directlyaway from it at speed 0.25 m/s.

a) What is the fq difference between the ultrasound emitted by the transducer and the ultrasound detected by the moving part of the heart? (answer says 375 Hz)

(b) What is the fq difference between the ultrasound emitted by the transducer and the ultrasound detected by the transducer after reflection from the moving part of the heart? (answer says 500 Hz)



For (a) I tried using the formula f- = (1-(vo/v))fo

where vo=0.25 and v=1500 and fo= 1.5 x 1000000 Hz and subtracting this value from 1.5x 1000000 Hz but I still cant get the write answer?

[availn]

Idk, could be a mistake in the answer to the first question? If the answer to the first is 250, then you are able to get to the second answer, using 375 doesn't seem to get you there.

[Starlight]

Idk, could be a mistake in the answer to the first question? If the answer to the first is 250, then you are able to get to the second answer, using 375 doesn't seem to get you there.

ah thanks availn!