Which of the following is not a type of friction ?

Which of the following cannot be used as a lubricant ?

Which of the following produces least friction ?

A train at rest tends to move from the platform and it attains a velocity of 100 km /h within a few second. While trying to come in motion it has to overcome the frictional force; that frictional force is __________________.

This _____________  is worn out and becomes smooth due to its repeated use on walls.

Friction is ______________________.

Powder is used in carrom board for  __________________

Which of the following is not a cause of friction ?

Which of the following is not a part of spring balance ?

By which of the following way we cannot decrease the friction ?