The Doppler shift of ultrasonic waves can measure the speed of blood in an artery. If the frequency of the stationary source is 100 kHz and the reflected sound has a Doppler shift of 300 Hz, what is the blood flow speed? (The speed of sound inside the body is 1500 m/s.)
a. 1.0 m/s
c. 2.2 m/s
b. 1.5 m/s
d. 3.3 m/s
C
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In a shear-thinning material, the applied shear stress divided by the viscosity is equal to the shear strain rate to a power that is equal to
(a) 1 (b) A number less than 1 (c) A number more than 1 (d) 2
Someone hits a tether ball to make it spin around a pole. The cord that attaches the tether ball to the central pole then winds around the pole. What happens to the angular speed of the tether ball during this process?
1.It decreases. 2.It increases. 3.It remains constant. 4.It cannot be determined.
The beam of electrons that hits the screen of an oscilloscope is moved up and down by:
a. varying the electron's charge. b. electrical charges on deflecting plates above and below the beam. c. gravity. d. a phosphorescent coating.
Which of the following molecules contains a phenol?
A) a B) b C) c D) b and c E) all of them