A turbofan jet engine has a large fan that sucks in air. Some of this air enters a set of compressors, is mixed with fuel in combustion chambers, and expands through the turbines that drive the fan. However, most of the air is accelerated by the fan through a bypass and exits together with the hot combustion exhaust.
In one type of engine, the ratio of the mass flow rate through the bypass is 2.5 times that through the combustion path. An aircraft fitted with this engine is in steady flight at 300 m/s. Air enters the jet engine at a rate of 300 kg/s. Bypass air exits at 600 m/s while combustion air exits at 1000 m/s. What is the thrust in kN of this engine?