why is static friction aleays greater than kinetic, and kinetic greater than rolling friction?
Static friction comes is experienced on an object is at rest. Kinetic friction is experienced when the object is in motion.
This would mean that static friction would be more as it keeps an object firmly at rest. The magnitude of the static friction keeps changing in response to the external force applied. However, if enough force is applied static friction is overcome and kinetic friction comes in to play. Kinetic friction is thus less as it allows an object to move.