The speed limit for the vehicle on a road is 108 `km//hr`. A policeman detects a drop of 25% in the pitch of the horn of a car as it passes him. Is the policeman justified in punishing the car driver for crossing the speed limit? (Velocity of sound = 350`m//s`.)

A car is moving with a speed of 72 km-hour^(-1) towards a roadside source that enits sound at a frequency of 850 Hz. The car driver listens to the sound while approching the source and again while moving away from the source after crossing it. If the velocity of sound is 340 ms^(-1) , the difference of the two frequencies the driver hears is

As speed limit is 120 km/h but speed of the car is less than it so that policeman does not punishing the car driver. Two sound notes have wavelengths 83/ 170 m and 83/ 172 m in the air.These noteswhen sounded together produce 8 beats per second.Calculate the velocity of sound in the air and frequencies of the two notes.

A motor car blowing a horn of frequency 124 vib//s moves with a velocity 72 km//hr towards a tall wall. The frequency of the reflected sound heard by the driver will be (velocity ofsound in air is 330 m//s )

Two cars moving in opposite directions approach each other with speed of 22 m//s and 16.5 m//s respectively. The driver of the first car blows a hom having a frequency 400 Hz. The frequency heard by the driver of the second car is [velocity of sound 340 m//s ]:

The pitch of the whistle of an engine appears to drop to (frac(5)(6)^(th) of original value when it passes a stationary observer. If the speed of sound in air in 350 m//s then the speed of engine is

A person is standing on a railway platform. An engine blowing a whistle of frequency 640 Hz approaches him with a speed of 72 km//hr . The frequency of the note heard by the person is (velocity of sound is 340 m//s )

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

A fly over bridge is in the form of a circular are of radius 30 m. Find the limiting speed at which a car can cross the bridge without losing contact with the road at the highest point. Assume the centre of gravity of the car to be 0.5 m above the road.

A bat,flying at velocity V_B = 12.5 m//s ,isfollowed by a car running at velocity V_C = 50 m//s . Actual directions of the velocities of the car and the bat are as shown in the figure below, both being in the same horizontal plane (the plane of the figure). To detect the car, the bat radiates ultrasonic waves of frequency 36 kHz. Speed of sound at surrounding temperature is 350 m//s . There is an ultrasonic frequency detector fitted in the car. Calculate the frequency recorded by this detector. The ultrasonic waves radiated by the bat are reflected by the car. The bat detects these waves and from the detected frequency, it knows about the speed of the car. Calculate the frequency of the reflected waves as detected by the bat. (sin 37° = cos 53° ≈ 0.6, sin 53° = cos 37° ≈ 0.8)

Two cars are moving on two perpendicular roads towards a crossing with uniform speeds of 72 km/hr and 36 km/hr. If first car blows horn of frequency 280 Hz, then the frequency of horn heard by the driver of second car when line joining the cars make 45^@ angle with the roads will be