In medicine, it is often important to monitor the blood flow in certain areas of the body. However, the movement of blood is difficult to monitor directly. Instead, some medical devices use the Hall effect, taking advantage of the fact that the blood flowing through a vein contains a considerable number of free ions.
Model the vein in a patient's arm to be of rectangular cross section, as shown in the figure, with a width w=4.00 mm and height ℎ=3.35 mm. The entire section of the vein is immersed in a constant magnetic field of ?=0.0955 T, pointing horizontally and parallel to the width. A medical device constantly monitors the resulting Hall voltage.
Suppose that medical precautions mandate that the speed of the blood flow for this particular component of the body should never drop below 21.40 cm/s. At what minimum Hall voltage VH, in millivolts, should the medical device be designed to trigger an alarm to the medical staff?
Trending nowThis is a popular solution!
Step by stepSolved in 2 steps
- At a given instant, the blood pressure in the heart is 1.1 x 104 Pa. If an artery in the brain is 0.38 m above the heart, what is the pressure in the artery? Ignore any pressure changes due to blood flow. Number Type your answer here Units Choose your answer herearrow_forwardA block of wood floats in fresh water with 0.724 of its volume V submerged and in oil with 0.859 V submerged. Find the density of (a) the wood and (b) the oil. (a) Number i Units (b) Number i Unitsarrow_forwardwhat is the answer??! help!arrow_forward
- Indiana Jones has acquired an artifact called the Amulet of Set, a piece of platinum jewelry in the shape of a snake. However, he suspects that he has a fake amulet, a replica planted by one of his enemies. He does not want to risk destroying the amulet in a chemical analysis, so he tries a more ancient method of identification. He first determines the mass of the amulet as it just hangs from a scale to be 1.28 kg. When he completely immerses the amulet in pure water, the reading on the scale drops to 1.12 kg. Draw a diagram showing the forces acting on the amulet as it is immersed. What is the buoyant force felt by the amulet? What is the volume of the amulet? Do not assume it is actually made of platinum! Is the amulet authentic? Justify your answer. *Problems involving the buoyant force are Newton’s Second Law problems, and should be solved with the same process!*arrow_forwardIn 1923, the United States Army (there was no United States Air Force at that time) set a record for in-flight refueling of airplanes. Using two refueling planes, an Airco DH-4B biplane was able to remain in flight for 39 h. During the flight, the refueling planes were able to air-transfer a total of 687 gallons of fuel to the plane in 9 refueling transfers. Assume that the refueling nozzle had a diameter of 1.45 in and each refueling took 2.45 min to perform. Calculate the velocity of the fuel through the nozzle. Assume that the fuel filled the entire cross-sectional area of the nozzle. velocity: m/sarrow_forwardA spherical shell has an outside radius of 2.40 cm and an inside radius of a. The shell wall has uniform thickness and is made of a material with density 4.52 g/cm3. The space inside the shell is filled with a liquid having a density of 1.27 g/cm3. (a) Find the mass m of the sphere, including its contents, as a function of a. m = g (b) For what value of a does m have its maximum possible value? a = cm (c) What is this maximum mass? m = g (d) Explain whether the value from part (c) agrees with the result of a direct calculation of the mass of a solid sphere of uniform density made of the same material as the shell. (e) Would the answer to part (a) change if the inner wall were not concentric with the outer wall? Yes Noarrow_forward
- A balloon filled with helium gas has an average density of ρb = 0.39 kg/m3. The density of the air is ρa = 1.23 kg/m3. The volume of the balloon is Vb = 0.045 m3. The balloon floats upward with acceleration a. a.) Express the acceleration of the balloon a in terms of the variables given in the problem statement, assuming upwards is the positive direction. b.) Calculate the numerical value of a in m/s2.arrow_forwardHow to solve Part B?arrow_forwardTo explore the bottom of a 10-m-deep lake, your friend Tom proposes to get a long garden hose, put one end on land and the other in his mouth for breathing underwater, and descend into the depths. Susan, who overhears the conversation, reacts with horror and warns Tom that he will not be able to inhale when he is at the lake bottom. Why is Susan so worried?arrow_forward
- Pressure cookers have been around for more than 300 years, although their use has strongly declined in recent years (early models had a nasty habit of exploding). How much force (in N) must the latches holding the lid onto a pressure cooker be able to withstand if the circular lid is 23.0 cm in diameter and the gauge pressure inside is 3.50 atm? Neglect the weight of the lid. Narrow_forwardThe pressure at the bottom of a glass filled with water (p = 1000 kg/m³) is P. The water is poured out and the glass is filled with glycerin (p = 1260 kg/m3). The pressure at the bottom of the glass is now which of the following? O equal to P O smaller than P O indeterminate O larger than Parrow_forwardThe aorta is the principal blood vessel through which blood leaves the heart in order to circulate around the body. (a) Calculate the average speed of the blood in the aorta if the flow rate is 5.0 L/min. The aorta has a radius of 10 mm. (b) Blood also flows through smaller blood vessels known as capillaries. When the rate of blood flow in the aorta is 5.0 L/min, the speed of blood in the capillaries is about 0.33 mm/s. Given that the average diameter of a capillary is 8.0 um, calculate the number of capillaries in the blood circulatory system.arrow_forward