Friction

According to Britannica, a friction is defined as the force that resists the sliding or rolling of one solid object over another. Friction is non-conservative force which means that work done against friction is path dependent. When the surfaces of two bodies are in contact and move relative to each other, the friction that is manifesting between two contact surfaces converts mechanical energy into thermal energy i.e. the work is transformed into heat. The best example of this energy transformation can be seen in rubbing two pieces of wood together to start a fire. In mechanical engineering the wear is important consequence caused by friction. This consequence of friction can lead to performance degratation and short exploatation period of product or can cause damage to components. There are many types of friction and these are dry friction, fluid friction, lubricated friction, skin friction, internal friction, radiation frictions, and other types of friction. In this case only sliding friction, and rolling firction. Here we will cover sliding friction and rolling friction.