pressure scale height we derived plane-parallel hydrostatic balance in class for an isothermal atmosphere. now let's see what it tells us. recall that the earth has mass m = 6 × 1024 kg and radius r 6378 km its atmosphere is made up of molecular nitrogen and oxygen, so that the average mass of a particle in the atmosphere is 30 proton masses (mp 1.66 x 10-27 kg) (a) presuming room temperature (300 k), calculate the scale height at sea level (b) how does it compare to the earth's radius? (c) the pressure at sea level is p 105 j m-3. calculate the mass column, of the atmosphere. y, (d) how deep would you have to go in t doubled from that he ocean so that the pressure is at sea level?

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 480 ? the index of refraction of the film is 1.34, and there is air on both sides of the film. express your answer in nanometers. hint 1. how to approach th

What component of earth’s atmosphere exists entirely as a result of photosynthesis?