$A$ police car moving at $22 \ m/s$ chases a motorcyclist. The policeman sounds his horn at $176 \ Hz$,while both of them move towards a stationary siren of frequency $165 \ Hz$. Calculate the speed of the motorcycle,if it is given that he does not observe any beats. (in $m/s$)

$A$ passenger is sitting in a train which is moving fast. The engine of the train blows a whistle of frequency $n$. If the apparent frequency of sound heard by the passenger is $f$, then:

$A$ motorcyclist is approaching a large wall with a velocity of $90\,km/hr$. $A$ car is chasing him with a velocity of $108\,km/hr$. If the car sounds a horn at $30\,Hz,$ the beat frequency heard by the motorcyclist is . . . . . . $Hz$. Take the velocity of sound $= 330\,m/s$.

$A$ train sounding a whistle of frequency $510 \,Hz$ approaches a station at $72 \,km/hr$. The frequency of the note heard by an observer on the platform as the train $(1)$ approaches the station and then $(2)$ recedes from the station are respectively (in hertz) (velocity of sound in air $= 320 \,m/s$).

The frequency changes by $10 \%$ as a sound source approaches a stationary observer with constant speed $V_s$. What would be the percentage change in the frequency as the source recedes from the observer with the same speed $\left(V_s < V\right)$ (in $.5$)?

Two whistles $A$ and $B$ each have a frequency of $500\,Hz$. $A$ is stationary and $B$ is moving towards the right (away from $A$) at a speed of $50\,m/s$. An observer is between the two whistles moving towards the right with a speed of $25\,m/s$. The velocity of sound in air is $350\,m/s$. Assume there is no wind. Then which of the following statements are true: