When a kinife is sharpened with the help of a rotation grinding stone, the speerk always travel tangentiall to it .Why ?

When the cutting edge of a knife is put against a fast rotating stone to sharpen it, sparks are seen to fly. Explain the reason.

Why does a stone sink when placed on the surface of water?

When a stone is thrown up, it reach it reaches a certain height and then stars falling down. Why ?

With the help of bionomial expansion, show that (4^(n)-3n) is always leaves remainder 1, when divided by 9.

Explain with the help of chemical equations what happens when- lime stone is heated?

When a stone is thrown on the surface of water, a wave travel out. From where does the energy came?

Why does a ray of light bend when it travels from one medium into another ?