Doppler Effect: When a Rocket Is Traveling Toward a Mountain

Multiple Choice

Doppler effect: When a rocket is traveling toward a mountain at 100 m/s, the sound waves from this rocket's engine approach the mountain at speed V. If the rocket doubles its speed to 200 m/s, the sound waves from the engine will now approach the mountain at speed

A) 4V.
B) 2V.
C) V.
D) V.