An observer is standing on a railway platform. He hears the whistle of railway engine moving towards him and then passing. He fells that

An observer is standing on a railway platfonn. He hears the whistle of a railway engine moving towards him and then passing. He feels that

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 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 head by the man changes with time ?

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 head by the man changes with time ?

A coolie standing on a railway platform observes that a train going in one direction takes 4 seconds to pass him. Another train of same length going in opposite direction takes 5 seconds to pass him. The time taken (in seconds) by the two trains to cross each other will be :