Question

1. You're driving your new Tesla convertible and can clearly hear other cars driving nearby. One of these cars honks their horn and your car, with its fancy apps and sensors, displays the horn sound as 760Hz. Your Tesla also registers the car as a Ferrari with a car horn of 795Hz. You are stopped at a stop light when their horn blares. Another of your Tesla's apps measures the air temperature to be 26°C. a) What is the speed of sound in this air? (1 point) b) How fast is the Ferrari driving relative to you? (4 points) c) Is the Ferrari driving toward or away from you? (1 point) d) The stop light turns green and you quickly reach 20 m/s. The Ferrari's horn appears broken as it continues to sound and the frequency app measures a lower value than before. What is the new frequency displayed and are you driving toward or away from the Ferrari? (4 points) e) You decide you like the Ferrari's horn sound so you change the Tesla to emit the 795Hz. What frequency do you hear from your car as you drive at 20 m/s? (2 points)

Answer 1

Given that it horn cound 7604E car horn 795Hz Sound Temperature (T) = 26c what is the speed of sound in this air ? We know that , Dependence of sound velocity on temperature is V = 331+0.6XT where, To Degse centigrade. is measured Here, > V= 331+0.6XT 331 + 0.6x 26 346.6 mis How fast is the relative mustang driving to you?

let us consider, Ý It The normal frequency of mustang is 795 HZ appearl 760Hz Cappears less) to you. we know that tomula, For doppler shift is, f itu, :) fo NA VS Where, f observed frequency actual frequency of the sound source Us = Velosity (It is mustang ) -> f - 760 H2 to = naster c from Egh ) 346.6 mis Cava) to 346.6 x(795) -760 > C)*(905) 346.6 + V

Ds 15-96 mis Hence, The velocity of the mostang relative is 15. 96 mls. to you Is The mustang driving toward or away from you lesen As the frequency to you, The mustang is chiving away appears from you. green & you The stop light turns quickly reach 20 ml let, The Grequency appears lower than normal you are udroviky ceway from the 1 mustang We know That formula tir Doppler shitt is V-vo fo f

Wher, V = Vrelosity of Observer { rest symbals bear the same meaning as ecorlic. frequency f = obrenied foa actual Velocity substitute in aqu ② = (1 o) to Vo=20mis 11-346.6 mis 60 795 HZ X 795 346.6 -20 346.6 749.13 mis 3 moslang's hom sound so you change The Corvette Emit the 79547 For As you are sitting in the car

5 with The Velocity of the car is Domis, you are also going a velocity of 20mis. so that Relative Velocity of you wor.ro, The car is zero. Hence, (795 Hz) sume Frequency will be tor You o Thank you.