2. Draw a conclusion about the effect of a moving source on the velocity of the waves in a medium? 3. How does the Doppler effect help explain why a car's engine sounds different as the car approaches you compared to after it passes you? 4. The Doppler effect is present in light waves as well. Red light has a slower frequency than blue light. What can you hypothesize about the motion of a distant star that appears "red- shifted" to astrophysicists