In class we examined the pressure, temperature and density variations in the lower 11km of the atmosphere (troposphere), assuming that the temperature drops linearly with altitude with a rate of -0.0065 k/m. from 11 to 20 km altitude, in the tropopause, the us standard atmosphere assumes the temperature to be constant. a) derive an expression for the variation of the atmospheric pressure with altitude h over the 11 to 25 km range, if the acceleration of gravity is constant. b) using the values of temperature and pressure at h=11km from the model used in the troposphere as new reference values for the tropopause, determine the pressure, temperature and density at 19 km altitude.