Class 9 Gravitation Important Questions

Gravitation Important Questions An object is thrown vertically upward and rises to height of 10 m. Calculate the (i) the velocity by which the object was thrown upward and (ii) the time taken by object to reach the highest point. The mass of earth is 6.4 x 1024 kg and that of the moon is […]

Class 9 Sound Notes

Sound Notes Sound:- Sound is a form of energy which produces a sensation of hearing in our ears. Vibration:- A kind of rapid to and fro motion of an object is called vibration. Sound is produced by vibrating objects. Wave:- A wave is a disturbance that moves through a medium when the particles of medium […]