A jet flies toward higher altitude at a constant speed of 1 963 m/s in a direction

Question:

A jet flies toward higher altitude at a constant speed of 1 963 m/s in a direction making an angle 0 with the horizontal (Fig. P17.64). An observer on the ground hears the jet for the first time when it is directly overhead. Determine the value of 0 if the speed of sound in air is 340 m/s.