WHAT DO YOU MEAN BY FRICTION? Friction is the force that resist the motion of an object that is moving relative to another. You can also say the force that produce resistance in relative motion of one surface over other. Friction is not a fundamental force. As you can say the gravitation is. Friction can operate between a given pair of solids, between a solid and a fluid or between a pair of fluids.



When does friction occur?? You can notice that friction always occur when two surface comes in contact with each other and you know why it happens, simply because both surfaces oppose the motion of each other.



Why does friction occur?? Friction occur due to the molecules adhesion or roughness of the surface. You can say friction occur because no surface is completely smooth. Even when a surface seems to be smooth, at micro or nano level it is rough. The very smooth surface that you can see with your eyes will have a very rough surface when seen through microscope.



Types of friction:{) As …