When you ascend or descend a great deal when driving in a car, your ears “pop,” which means that the pressure behind the eardrum is being equalized to that outside. If this did not happen, what would be the approximate forceon an eardrum of area 0.20 cm2 if a change in altitude of 1250 m takes place?

In about 1657, Otto von Guericke, inventor of the air pump, evacuated a sphere made of two brass hemispheres (Fig. P15.62). Two teams of eight horses each could pull the hemispheres apart only on some trials and then with greatest difficulty, with the resulting sound likened to a cannon firing. Find the force F required to pull the thin-walled evacuated hemispheres apart in terms of R, the radius of the hemispheres; P, the pressure inside the hemispheres; and atmospheric pressure P0. Figure P15.62

Bird bones have air pockets to reduce their weight—this also gives them an average density significantly less than that of the bones of other animals. Suppose an ornithologist weighs a bird bone air and in water and finds its mass is 45.0 g ad its apparent mass when submerged is 3.60 g (assume the bone is watertight.)(a) What mass of is displaced? (b) What is the volume of the bone? (c) What is its average density?

In an immersion measurement of a woman's density, she is found to have a mass of 62.0 kg in air an apparent mass of 0.0850 kg completely submerged with lungs empty. (a) What of water does she displace? (b) What is her volume? (c) Calculate her density. (d) If her lung capacity is 1.7S L, is she able to that without treading water with her lungs filled air?

An oil gusher shoots crude 25.0 m the through a pipe with a 0.100-m diameter. Neglecting resistance but not resistance of the pipe, and assuming laminar flow, calculate pressure at be entrance of be 50.0-m-Iong vertical pipe. Take of the oil to be 900 kg/m3 and its viscosity to be 100(N/m2) s (or 1.00 Pa s). Note that you must take into account the pressure due to 50.0-m column of oil in pipe.

The left ventricle of a resting adult's heart pumps blood at a flow rate of 83.0 cm3/s , increasing its pressure by 110 mm Hg, its speed from zero to 30.0 cm/s, and its height by 5.00 cm. (All cumbers are averaged over the entire heartbeat) Calculate the total power output of left ventricle. Note that most of the power is used to increase blood pressure.

Using the equation of the previous problem, find the viscosity of motor oil in which a steel ball of radius 0.8 mm falls a terminal speed of 4.32 cm/s. The densities of the ball and the oil are 7.86 and 0.88 g/mL, respectively.

How tall must a water-filled manometer be to measure blood pressures as high as 300 mm Hg?

A frequency quoted rule of thumb aircraft design is that wings should produce about 1000 N of lift per square meter of wing. (The fact that a wing has a top and bottom surface does not double its area.) (a) At takeoff, an aircraft travels at 60.0 m/s, so that the air speed relative to the bottom of the wing is 60.0 m/s. Given be sea level density of air as 1.29kg/m3, how fast must it move over be upper surface to create the ideal lift? (b) How fast must air move over the upper surface at a cruising speed of 245 m/s and at an altitude where air density is one-fourth that at sea level? (Note that his not all of be aircraft's lift—some comes from be body of the plane, some from engine thrust, and so on. Furthermore, Bernoulli's principle gives approximate answer because flow over wing creates turbulence.)

Two thin-walled drinking glasses having equal base areas but different shapes, with very different cross-sectional areas above the base, are filled to the same level with water. According to the expression P = P0 + gh, the pressure is the same at the bottom of both glasses. In view of this equality, why does one weigh more than the other?