What is the relationship between friction and velocity? ( please be a bit detailed on it and be 3-4 sentences long.)

Friction is typically unrelated to speed. When the surfaces start to melt or otherwise change because of heat build up or inability to follow the surface then things will change.Friction is related to velocity in that it acts to reduce velocity. In other words it causes moving objects to decelerate.The friction force may also act as one of the forces in a moment that is causing motion. If the motion is rotary, or following any path, then the friction force may be simply a part of the system of forces that influences motion.Hope It's Helps! :)

The rocks expand when there hot/warm  and contract when they are cold.