Shock Waves: a Supersonic Plane Passes Overhead at a Speed

Multiple Choice

Shock waves: A supersonic plane passes overhead at a speed of 500 m/s. If you hear the sonic boom (shock wave) 4.00 s after the plane is directly overhead, at what altitude is the plane flying? Assume the speed of sound in air is 340 m/s.

A) 1.36 km
B) 2.16 km
C) 1.85 km
D) 2.45 km
E) The plane is not flying fast enough to produce a shock wave.