$A$ motorcycle starts from rest from a stationary source of sound and moves away from the source with a uniform acceleration $2 \,m/s^2$. The distance travelled by the motorcycle when the person on it hears the sound of frequency which is $94 \%$ of the true frequency is nearly (speed of sound in air $= 330 \,m/s$): (in $\,m$)

$A$ person with a vibrating tuning fork of frequency $338 \,Hz$ is moving towards a vertical wall with a speed of $2 \,ms^{-1}$. The velocity of sound in air is $340 \,ms^{-1}$. The number of beats heard by that person per second is

$A$ source of sound of frequency $500 Hz$ is moving towards an observer with velocity $30 m/s$. The speed of sound is $330 m/s$. The frequency heard by the observer will be .... $Hz$

$A$ train,standing in a station-yard,blows a whistle of frequency $400\; Hz$ in still air. The wind starts blowing in the direction from the yard to the station with a speed of $10\; m s^{-1}$. What are the frequency,wavelength,and speed of sound for an observer standing on the station's platform? Is the situation exactly identical to the case when the air is still and the observer runs towards the yard at a speed of $10\; m s^{-1}$? The speed of sound in still air can be taken as $340\; m s^{-1}$.

Two cars $A$ and $B$ are moving away from each other in opposite directions. Both cars are moving with a speed of $20 \, ms^{-1}$ with respect to the ground. If an observer in car $A$ detects a frequency of $2000 \, Hz$ from the sound source in car $B$,what is the natural frequency of the sound source of car $B$ (in $Hz$)? (Speed of sound in air $= 340 \, ms^{-1}$)

$A$ source and a detector move away from each other in the absence of wind with a speed of $20 \, m/s$ with respect to the ground. If the detector detects a frequency of $1800 \, Hz$ of the sound coming from the source,then the original frequency of the source,considering the speed of sound in air to be $340 \, m/s$,will be (in $Hz$):