the frictional force that occurs in kinetic friction is called "kinetic friction". when the force exerted on an object is greater than the maximum static friction force, the object begins to move. after starting to move, if the force applied is reduced, the object will stop moving again. this situation shows that after the object moves, there is still a force that prevents the object from moving, that is, there is still frictional resistance. the friction generated when an object moves is called kinetic friction.

dynamic friction: f_k=μ_k*N

here:

μ_k = dynamic friction factor

n = normal force