In Physic class, we learn mostly about friction. We mainly practicing problems after we clearly understand the topic. Currently, our topics are connected to Static and Kinetic friction. Static friction is Static friction is a force that keeps an object at rest. It must be overcome to start moving the object. Moreover, static friction has an equal magnitude in the opposite direction. Kinetic friction is a force that acts between moving surfaces. The magnitude of the force depends on the coefficient of kinetic friction between the two kinds of material.