posted by itufizik .
You are traveling in a car toward a hill at a speed of 42.1 mph. The car's horn emits sound waves of frequency 251 Hz, which move with a speed of 343 m/s.
a) Determine the frequency with which the waves strike the hill.
b) What is the frequency of the reflected sound waves you hear?
c) What is the beat frequency produced by the direct and the reflected sounds at your ears?