What type of kinetic friction is used to roll in -line skates?

In-line skates primarily utilize static friction to roll, as it is the friction between the wheels and the surface that allows them to grip and propel forward without slipping. Once in motion, the friction encountered is kinetic friction, which is typically lower than static friction, allowing for smoother gliding. However, the primary force enabling the skater to push off and maintain speed is the static friction between the wheels and the ground during the initial push.