Friction is the resistance to motion when two objects are in contact. It depends on the type of surfaces in contact and the normal force pressing them together.
Formulas
formula for frictional force (Ff) is:
Ff = μ * Fn
Where:
μ: Coefficient of friction
Fn: Normal force (force perpendicular to the surfaces in contact)
There are two types of friction:
Static Friction: Friction between objects that are not moving relative to each other.
Kinetic Friction: Friction between objects that are sliding past each other.