For this problem, assume that high frequency sound waves travelthrough human tissue at 1500 m/s (about the speed of sound inwater).
a) Measurements of the blood flow in the ascending aorta shows amaximum speed of 92.00 cm/sec. Assuming the ultrasound frequencyused is 2.000000 MHz (the paper uses 2.25 MHz), calculate thefrequency as seen by the blood that is traveling toward theultrasound transducer at 92.00 cm/s. The transducer, which bothtransmits and receives the sound waves, is not moving. It’s fine touse lots of significant figures here, so you can see the differencein frequency.
b)Calculate the shift in frequency for the waves received by thetransducer after the waves have reflected off the flowing bloodback to the transducer. The shift in frequency is the difference infrequency between the incoming and outgoing waves.
c)The transducer is then re-positioned so that the blood isflowing away from the transducer. Again, calculate the shift infrequency for the waves received by the transducer after the waveshave reflected off the flowing blood back to the transducer. [
d)For (c), calculate the magnitude of the percentage differencebetween the incoming and outgoing frequencies. (It’s essentiallythe same magnitude for part (b), too, because the speed of theblood is so much smaller than the speed of sound.)
