6. (a) It can be shown that the Knudsen number is a ratio containing the Reynolds number and the Mach number. State the Knudsen number in terms of Reynolds number and Mach number. Over which Knudsen number range can the continuum approach to flow problems still apply? (b) For flight at relevant Mach numbers and Knudsen numbers it is possible to use Newtonian theory in order to calculate forces on flight vehicles. State all assumptions underpinning Newtonian theory and describe limitations of its use. (c) A sin 0 0 V.. Area A A flat plane is placed with an angle 8 to horizontal direction as shown in the figure above with air flowing in the free stream velocity Vo density poo, and pressure poo. Use Newtonian theory to determine the equation for calculating the pressure coefficient. (d) Part of a space vehicle can be approximated to be a flat plate. Given a flight Mach number of 30 and that the plate is at an angle of 6 degrees to the flow, calculate the pressure coefficient for the plate. Assume that the plate has negligible thickness.