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## Homework Statement

At the Indianapolis 500, you can measure the speed of cars just by listening to the difference in pitch of the engine noise between approaching and receding cars. Suppose the sound of a certain car drops by a factor of 1.50 as it goes by on the straightaway. How fast is it going? (Take the speed of sound to be 343 m/s.)

answer given in km/h

## Homework Equations

v= (1- (f/(f prime/1.5))v

where the second v is the speed of sound.

Sorry it isnt a cleaner equation, I couldn't figure out how to get my mathtype equation from microsoft word here.

## The Attempt at a Solution

The equation above is my attempt at a solution, since the sound of the cars frequency drops by 1.5 thats what I divided my f prime by. I just dont know how to figure out the f values. Maybe I am using the wrong equation, I just can't figure out any other way to solve for the speed of the car. Any hints would be greatly appreciated and I thank you for your time.