Problem 4 - A hybrid rocket with an initial mass of minim; = 900 kg operates in space. The fuel is parafn with a density 0.93 gm/cm3 and the Oxidizer is nitrous oxide. The Oxidizer mass ow rate is held xed at 2.4 X 104 gm/sec. The motor has a 10mm diameter nozzle throat, 30 cm diameter exit, and a cylindrical port 143 cm long. The initial port radius is 8.75 cm. At the end of the burn the port radius is 15.5 cm. The regression rate law is 7'\" = 0.0356'2'6 cm/ sec. A calculation using CEA shows that 0* = 1.64 x 105 cm/ sec where 0* is dened by m = Pt2A*/C* and the effective nozzle exit velocity is C = 2.8 x 105 can/sec. 1) When the fuel is all burned the oxidizer ow is turned off. Determine the time when this occurs. 2) Determine the total mass ow rate and motor thrust at the beginning and end of the burn. 3) Determine the chamber pressure at the beginning and end of the burn