$A$ musician on a moving vehicle plays a tone at $880 \ Hz$. When the vehicle is approaching a listener, the listener receives it as an $888 \ Hz$ tone. What is the speed of the vehicle (in $m \ s^{-1}$)? (Assume the velocity of sound is $333 \ m \ s^{-1}$)

When the source of sound and the observer both are moving towards each other,the observer will hear:

$A$ speeding motorcyclist sees a traffic jam ahead. He slows down to $36\, km\, h^{-1}$. He finds that the traffic has eased and a car moving ahead of him at $18\, km\, h^{-1}$ is honking at a frequency of $1392\, Hz$. If the speed of sound is $343\, m s^{-1}$,the frequency of the honk as heard by him will be .... $Hz$.

$A$ car sounding a horn of frequency $1200 \text{ Hz}$ passes a stationary observer. The ratio of frequencies of the horn noted by the observer before and after passing the car is $7:5$. If the speed of sound is $V$,the speed of the car is:

$A$ bat is flitting about in a cave,navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is $40\; kHz$. During one fast swoop directly toward a flat wall surface,the bat is moving at $0.03$ times the speed of sound in air. What frequency (in $kHz$) does the bat hear reflected off the wall?

$A$ car travelling at a speed of $54 \ km/h$ towards a wall sounds a horn of frequency $400 \ Hz$. The difference in the frequencies of two sounds, one received directly from the car and the other reflected from the wall, noticed by a person standing between the car and the wall is (speed of sound in air is $335 \ m/s$):