Adoppler flow meter is used to measure the speed of blood flow. transmitting and receiving elements are placed on the skin, as shown in the figure below. typical sound-wave frequencies of about 5.0 mhz are used, which have a reasonable chance of being reflected from red blood cells. by measuring the frequency of the reflected waves, which are doppler-shifted because the red blood cells are moving, the speed of the blood flow can be deduced. "normal" blood flow speed is about 0.1 m/s. suppose that an artery is partly constricted, so that the speed of the blood flow is increased, and the flow meter measures a doppler shift of 780 hz.

what is the speed of blood flow in the constricted region? the effective angle between the sound waves (both transmitted and reflected) and the direction of blood flow is 45o, assume the velocity of sound in tissue is 1540 m/s.

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit

Increasing the pressure on one spot of a fluid will increase the pressure everywhere else in the fluid a. pascals principal b. archimedes' principal c. bernoulli's principal

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. it strikes a red glider that has mass 0.600 kg and that is initially at rest. after the collision, the blue glider is moving to the left with a speed of 3.00 m/s.(a) what are the magnitude and direction of the velocity of the red glider after the collision? (b) is this collision elastic?