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3. Draw and calculate the frequencies of the first harmonics for the following two tubes (a and b) by taking the speed of sound as 340 m/s. a. A tube open at both ends (tube length is C m) (10 points) =\\ b. A tube opens at one end (tube length is C m) (10 points) c. A fast-moving car coming with (D+50) m/s towards you while you are standing on the sidewalk. The engine produces sound at 800 Hz and the speed of sound is 340 m/s. I. What is the true frequency of the car? (5 points) D = 10 II. What is the frequency you hear? (10 points) III. If the car moves away from you what is frequency you hear? (10 points)