# Types of Friction

In physics, friction is the force that opposes perpendicular motion when two surfaces are pressed together. There are many types of frictional forces including kinetic and static friction. Kinetic friction is a function of the normal force between surfaces in contact and it varies with velocity. Static or Coulomb’s Law Friction is present even when there’s no relative movement because of the electrical charges on both surface’s surfaces which resist each other through electrostatic interactions.

I am writing about the types of friction in physics. There are three types: static, kinetic, and fluid. Static is when two surfaces are touching but not sliding relative to each other. Kinetic is when there’s a force that pushes one surface against another and they start moving, like if you’re holding a book on your lap and it starts slipping off because you’ve been sitting still for too long. The third type of friction is fluid, which happens in fluids such as water or air when one object moves over another object in the same fluid at different speeds.