Home
Class 11
PHYSICS
(i) A straight railway track is at a dis...

(i) A straight railway track is at a distance ‘d’ from you. A distant train approaches you travelling at a speed `u (lt` speed of sound`)` and crosses you. How does the apparent frequency `(f)` of the whistle change with time (`f_(0)` is the original frequency of the whistle). Draw a rough `f` vs `t` graph.
(ii) A bat is tracking a bug. It emits a sound, which reflects off the bug. The bat hears the echo of the sound `0.1` seconds after it originally emitted it. The bat can tell if the insect is to the right or left by comparing when the sound reaches its right ear to when the sound reaches its left ear. Bat’s ears are only `2 cm` apart. Bats also use the frequency change of the sound echo to determine the flight direction of the bug. While hovering in the air (not moving), the bat emits a sound of `40.0 kHz`. The frequency of the echo is `40.4 kHz`. Assume that the speed of sound is `340 m//s`.
(a) How far away is the bug?
(b) How much time delay is there between the echo reaching the two ears if the bug is directly to the right of the bat?
(c) What is the speed of the bug?

Promotional Banner

Similar Questions

Explore conceptually related problems

An automobile moving at 30 m/s is approaching a factory whistle that has a frequency of 500 Hz. If the speed of the sound in air is 340 m/s, then the apparent frequency of the whistle as heard by the driver is

when a source of sound of frequency f crosses stationary observer with a speed v_(s) (lt lt speed of sound v) , the apparent change in frequency Δf is given by

A man is standing on a railway platform listening to the whistle of an engine that passes the man at constant speed without stopping. If the engine passes the man at time t_0 How does the frequency f of the whistle as heard by the man changes with time.

A train is moving at a speed of 72 kmph towards a station sounding a whistle of frequency 640Hz. What is the apparent frequency of the whistle as heard by a man standing on the platform when train approaches towards him.

A man standing on a platform observes that the frequency of the sound of a whistle emitted by a train drops by 140 Hz. If the velocity of sound in air is 330 m/s and the speed of the train is 70 m/s, the frequency of the whistle is

A man standing on a platform observes that the frequency of the sound of a whistle emitted by a train drops by 140 Hz. If the velocity of sound in air is 330 m/s and the speed of the train is 70 m/s, the frequency of the whistle is

when a source of sound of frequency f crosses stationary observer with a speed v_(s) (lt lt speed of sound v) , the apparent change in frequency Dealtaf is given by