When a car is driving up a hill, is the friction between the tires and the ground static friction or kinetic friction?
If you are not spinning your wheels on the pavement, it is static friction between the tire and ground. If the wheels start spinning, it is kinetic friction.
Since static friction provides a greater frictional force than kinetic friction, spinning tires should be avoided. That is the theory behind ABS braking, and why you shouldn't just spin your tires faster when trying to move on slippery pavement.
Paul Walorski, B.A., Part-time Physics/Astronomy Instructor
'The mathematician's patterns, like the painter's or the poets, must be beautiful; the ideas, like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics.'