he pressure variation in any static fluid is described by the basic pressure relationship dzdp=g Where P is the density, g is the gravitational acceleration, p is the pressure and z is measured upward. For ideal gases, the equation of state is p=RT Where R is the gas constant (R=0.287kJ/kg/K for air) and T is the temperature measured in Kelvin. (a) Start from equation 3.1 with coordinate transformation, and the ideal gas law, show that the pressure variation in the atmosphere is given as: p=ps(1TsBz)8.R8s Where R is the gas constant for air, B is the lapse rate dxdT=km6.5K,Ts=(15+273)K,R=287 J/K/kg, subscript s= sea-level (b) Determine the pressure and density at z=9900m