In the day time, when we go to the sea the air blows towards us and does not go towards the sea. Explain.

A train, standing in a station -yard, blows a whistle of frequency 400 Hzin still air. The wind starts blowing in the direction from the yard to the station with a speed of 10 ms^(-1) . What are the frequency, wavelength and speed of sound for an observer standing on the station's platforms ? Is the situation exactly identical to the case when the air is still and the observer runs towards the yard at a speedof 10 ms^(-1) ?The speed of sound in still air can be taken as 340 ms^(-1) .

A person wants to 9 children to an exhibition by taking 3 at a time in all possible ways. How many times does a particular child go to the exhibition and how many times does the person go to the exhibition.

Wet clothes dry after some time - where does the water go?

Many great rivers flow towards the equator, what effect does the sediment they carry to sea have on the rotation of the earth?