A rocket is moving at a speed of 200m/s towards a stationary target. While moving, it emits a wave of frequency 1000Hz. Calculate the frequency of the sound as detected by the target. (Velocity of sound in air is 330m/s )

Explanation

The target is the source (as it is the source of echo) and the rocket's detector if the observer who intercepts the echo of frequency v'. Hence the frequency of the echo as detected by a detector attached to the rocket is
`v''=(v+v_(0))/(v-v_(s))xxv=(330+200)/(330-0)xx2538.5`
`=(530)/(330)xx2538.5`
`~~4077Hz`.