149 An engine moving towards a wall with a velocity 50 m

Last updated: 6/12/2023

149 An engine moving towards a wall with a velocity 50 m emits a note of 1 2 kHz The speed of sound in air is 3 m s The frequency of the note after reflection from the wi as heard by the driver of the engine is 1 2 4 kHz 2 0 24 kHz 3 1 6 kHz 4 12 kHz