© Department of Physics, University of Guelph
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1. What is the tension in a capillary wall if the blood pressure is 30 mm Hg and the radius 4 µm?
2. The tension in the wall of an artery of radius 5.00 × 103 m is 650 N m1. Further from the heart, a constriction in the same vessel decreases the cross-sectional area to one half of what it was. What is the tension in the wall at this point? Assume flow is steady and that v = 0.700 m s1 at the wider portion. Neglect viscosity and assume negligible change in elevation.
3. An extensible tube was found to stretch to a radius of 1.0 × 103 m when the pressure inside was greater than the outside pressure by 60 N m2. A student was given the problem of finding the conditions under which the end of the tube could be placed in a liquid and a hemispherical bubble of radius 1.0 × 103 m be blown into it. The student was surprised to find that it did not matter how far down into the fluid the tube was placed and that it could be done only for a particular value of the surface tension of the fluid. What is the surface tension?
4. Draw graphs of tension (in N m1) versus radius for