Consider an airplane with a jet engine attached to the tail section that expels combustion gases at a rate of $18$ kg$/$s with a velocity of V$=255$m$/$sV$=255$m$/$s relative to the plane. During landing, a thrust reverser $($which serves as a brake for the aircraft and facilitates landing on a short runway$)$ is lowered in the path of the exhaust jet, which deflects the exhaust from rearward to $120.$