Chapter 13, Problem 105GP

Why is the Earths atmosphere denser near sea level than it is at a high altitude? Be sure to explain why the atmospheres density is not uniform and why the air isnt all in contact with the Earths surface.

A manometer containing water with one end connected to a container of gas has a column height difference of 0.60 m (Fig. P15.72). If the atmospheric pressure on the right column is 1.01 105 Pa, find the absolute pressure of the gas in the container. The density of water is 1.0 103 kg/m3. FIGURE P15.72

You have probably noticed that carrying a person in a pool of water is much easier than carrying a person through air. To understand why, find the buoyant force exerted by air and by water on the person. Assume the average volume of a person is 0.45 m3, and that the person is submerged in air and water respectively.

In about 1657. Otto von Guericke, inventor of the air pump, evacuated a sphere made of two brass hemispheres (Fig. P9.89). 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 P9.89

A frequently quoted rule of thumb in 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 54 m/s, so that the air speed relative to the bottom of the wing is 54 m/s. Given the sea level density of air to be 1.29 kg/m^3, how fast must it move over the upper surface to create the ideal lift? b. How fast must air move over the upper surface at a cruising speed of 242 m/s and at an altitude where air density is one-fourth that at sea level?

Calculate the work done in increasing the radius of a soap bubble in air from 1 cm to 2 cm. The surface tension of the soap solution is 30 dx/cm.

Q24. The buoyancy force on the 640-kg balloon is F= 6 kN, and the air force acting {C1 ·ti- C2 · Vi j} N, when tis time in on the balloon is Fair = seconds, constants C = 40 and C2 = 160. If the balloon starts from rest, determine its speed after 26 seconds. Neglect the size of the balloon but don't neglect its weight. Please pay attention: the numbers may change since they are randomized. Your answer must include 2 places after the decimal point, and proper SI unit. Take g = 9.81 m/s2. Fair F = 6 kN Your Answer: Answer units

A frictionless and leak-free piston moves up and down a cylinder whose diameter and height are 10 cm and 1 m, respectively (see the sketch). At equilibrium, the downward force on the piston, due to the atmospheric pressure (100 kPa) and the gravitational force on the mass of the piston, is equal to the magnitude of the upward force on the piston, due to the pressure of gas in the cylinder. The cylinder is filled with NH3 at 150 kPa and 20 ° C, which maintains the piston to its initial location of H = 80 cm. Assuming that the ideal gas law is applicable - Pirton NH, (a) Calculate the mass of the piston. (b) Calculate the mass of NH3 in the cylinder. Use, R = 0.4882 kJ/kg.K %3D A metal weight with a mass of 40.03 kg is now placed on the piston, which causes it to move downward in the cylinder. (c) Calculate the pressure in the cylinder and the piston location (H) if the temperature of Ammonia remains constant at 20 ° C. (d) Find the temperature to which the NH3 in the cylinder must be…

You have entered a model rocket contest with your friend, Tiffany.  You have been working on a pressurized rocket filled with nitrous oxide.  Tiffany has determined the minimum atmospheric pressure at which the rocket fuel is stable.  Based not hat value, and the equations given below, your task is to determine the optimum launch angle and initial velocity to maximize flight time.  The goal is to re-use your rocket capsule, so you really want to avoid a fuel explosion. The atmospheric pressure varies with elevation according to the equation: P(h)= 14.7e−h/10. where p is the pressure in psi and h, is an elevation in miles above sea levels. The height (in feet) of a rocket launched at an angle α degrees with the horizontal and an initial velocity, vo in feet/second, t  seconds after launch is given by the equation h(t)=-16t^2+vo*t*sin(α). 1) If Tiffany has determined that the minimum safe pressure is 11 pounds per square inch, at what altitude will the rocket explode?  Report your result…