# Physics

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The siren of a police car produces a sound of frequency 420Hz.A man sitting next to the road notices that the pitch of the sound changes as the car moves towards and then away from him.1- WRITE DOWN THE NAME OF THE PHENOMENON. 2-ASSUME THAT THE SPEED OF THE SOUND IN AIR IS 340m.s^-1. CALCULATE THE FREQUENCY OF THE SOUND OF THE SIREN OBSERVED BY THE MAN,WHEN THE CAR IS MOVING TOWARDS HIM AT A SPEED OF 16m.s^-1.

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