5. A rocket has a total lift-off mass of 1.2x10 kg. 80% of the mass is the propellant fuel. The rocket consumes fuel at a rate of 5000 kg/s and the exhaust gases have a constant velocity of 3 km/s. Take gas jet exhaust exit diameter as 1.25 m, static pressure at the jet rocket exhaust as 125 kPa, and ambient pressure around the rocket as 101325 Pa. Calculate: a) the time for all the fuel to be used b) the thrust produced c) the net force on lift-off d) the initial acceleration.