Explain how lubricants help in reducing friction

A good lubricant must have

Explain static friction

What are the methods of reducing friction?

Explain how with the help of Bernoulli's principle, aeroplane can be lifted.

Explain the origin of friction.

Explain Rolling Friction OR What is rolling friction ? How does it arise

Explain Kinetic Friction.

How do skin and lungs help in Excretion? OR Explain role of lungs and skin in excretion?

Explain trend in reducing property of dioxide of Group 16

Answer the following : Explain with the help of graph , the variation of atmospheric pressure with height .