Physics

posted by .

Ultrasound reflected from an oncoming bloodstream that is moving at 30 cm/s is mixed with the original frequency of 1.3 MHz to produce beats. What is the beat frequency? (Velocity of sound in blood = 1540 m/s.)

Beat frequency = Hz

HELP: This problem involves two Doppler shifts.

HELP: In the first shift, the source is fixed and the observer is the moving blood. Why?

HELP: In the second shift, the source is the moving blood and the observer is fixed. Why?

HELP: It might be helpful to think of a tiny ultrasound recorder mounted on a blood cell. The recording happens when the ultrasound arrives at the cell, and the echo leaves when the recorded sound is "played back".

HELP: Once you know the frequency of the Doppler-shifted echo, how do you find the beat frequency between the echo and the original frequency?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A Doppler blood flow meter emits ultrasound at a frequency of 5.0 MHz. What is the beat frequency between the emitted waves and the waves reflected from blood cells moving away from the emitter at 0.15m/s?
  2. College Physics

    Finally, your friend's twin engine jet airplane lands. As it stands on the runway, you hear the sound of the engines getting louder and softer, rhythmically once every 2.3 s. The average frequency you hear is 3650 Hz. What are the …
  3. physics

    A car traveling at 24.3 m/s honks its horn as it directly approaches the side of a large building. The horn produces a long sustained note of frequency f0 = 213 Hz. The sound is reflected off the building back to the car's driver. …
  4. physics

    A car traveling at 22.1 m/s honks its horn as it directly approaches the side of a large building. The horn produces a long sustained note of frequency f0 = 235 Hz. The sound is reflected off the building back to the car's driver. …
  5. physics

    You are traveling in a car toward a hill at a speed of 40.8 mph. The car's horn emits sound waves of frequency 243 Hz, which move with a speed of 340 m/s.The frequency with which the waves strike the hill is 254.7Hz and the frequency …
  6. physical

    You are traveling in a car toward a hill at a speed of 42.1 mph. The car's horn emits sound waves of frequency 251 Hz, which move with a speed of 343 m/s. a) Determine the frequency with which the waves strike the hill. b) What is …
  7. phy

    Doppler ultrasound is used to measure the speed of blood flow. If the speed of the red blood cells is v, the speed of sound in blood is u, the ultrasound source emits waves of frequency f, and we assume that the blood cells are moving …
  8. Math

    On an EKG strip a nurse determines that a patient's heart is beating 5 times every 4.5 seconds. Calculate the time for each heart beat. I don't really understand what the question is asking for?
  9. physics

    Two identical sources S1 and S2 are moving towards an observer P. The two sound sources S1 and S2 produce notes of frequency 500hz. If the speed of S1 and S2 are 20ms-1 and 23ms-1 respectively, calculate the beat frequency heard by …
  10. Physics - sound

    How can one recognise the beat frequency from a graph?

More Similar Questions