Q1. The source of a sound wave is stationary. The observer is moving toward the source. There's a steady wind blowing from the observer to the source. How does the wind change the observed frequency?

A. The wind magnifies the Doppler effect and increases the frequency

B. The wind minimizes the Doppler effect and increases the frequency

C. The wind magnifies the Doppler effect and decreases the frequency

D. The wind minimizes the Doppler effect and decreases the frequency

Answer is A. How does the wind increase the observed frequency? Could anyone explain this for me? EK explanation is "add the opposite direction of velocity to both source and observer.."

Q2. An interstellar gas circles the core of earth's galaxy. If the wavelength of the light reflecting off the gas coming toward the earth is 499nm, and the wavelength of light reflecting off the gas moving away from earth is 501nm, what is the speed of gas?

A. 4.2 x 10^4 m/s

B. 1.2 x 10^5 m/s

C. 6.0 x 10^5 m/s

D. 1.5 x 10^11 m/s

I have no idea how to approach this problem. Help?

A. The wind magnifies the Doppler effect and increases the frequency

B. The wind minimizes the Doppler effect and increases the frequency

C. The wind magnifies the Doppler effect and decreases the frequency

D. The wind minimizes the Doppler effect and decreases the frequency

Answer is A. How does the wind increase the observed frequency? Could anyone explain this for me? EK explanation is "add the opposite direction of velocity to both source and observer.."

Q2. An interstellar gas circles the core of earth's galaxy. If the wavelength of the light reflecting off the gas coming toward the earth is 499nm, and the wavelength of light reflecting off the gas moving away from earth is 501nm, what is the speed of gas?

A. 4.2 x 10^4 m/s

B. 1.2 x 10^5 m/s

C. 6.0 x 10^5 m/s

D. 1.5 x 10^11 m/s

I have no idea how to approach this problem. Help?

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