CoachFriction between touching surfaces opposes their relative sliding. Static friction acts while they do not slide, adjusting itself up to a maximum to cancel whatever tries to start the slide; kinetic friction, once sliding has begun, is roughly constant, directed against the sliding, and usually weaker than the static maximum.
Examples
Example 16.13 (Pushing the wardrobe)
Push a wardrobe gently: it does not move — static friction cancels your . Push harder: at some it lurches into motion, then slides with less effort — the weaker kinetic friction has taken over.