When a source of sound crosses a stationary observer,the change in apparent frequency of sound observed by the observer,when $V_s << V$,will be -

$A$ small source of sound vibrating at a frequency $500 Hz$ is rotated along a circle of radius $\frac{100}{\pi} cm$ at a constant angular speed of $5$ revolutions per second. The minimum and maximum frequency of the sound observed by a listener situated in the plane of the circle is (Speed of sound is $332 ms^{-1}$)

$A$ whistle of frequency $660 \,Hz$ moves in a circle of radius $1 \,m$ at an angular speed of $10 \,rad/s$. The highest frequency heard by a listener at a long distance and at rest with respect to the center of the circle is (Let speed of sound $= 340 \,m/s$.) (in $\,Hz$)

Two sirens situated one kilometer apart are producing sound of frequency $330 \ Hz$. An observer starts moving from one siren to the other with a speed of $2 \ m/s$. If the speed of sound is $330 \ m/s$,what will be the beat frequency heard by the observer?

$A$ car blowing a horn of frequency $350\, Hz$ is moving towards a wall with a speed of $5\, m/s$. The beat frequency heard by a person standing between the car and the wall is ..... $Hz$ (speed of sound in air $= 350\, m/s$).

$A$ student holds a tuning fork oscillating at $170 \,Hz$. He walks towards a wall at a constant speed of $2 \,ms^{-1}$. The beat frequency observed by the student between the tuning fork and its echo is (Velocity of sound $=340 \,ms^{-1}$ ) (in $\,Hz$)