A background check is required of all applicants for the above licenses or. certificates. The following is required prior to going to Greeley/Weld Criminal. Justice Records Section, 1551 N. 17th Avenue, Greeley, CO for the background. check.
Friction is a force that acts against a moving object to slow it down. A type of friction is air resistance. Friction opposes the direction in which the object is moving, causing the object to decrease in speed, or stop all together.
Friction. 1  Dry Friction - This is what we've been mostly talking about here. Dry friction occurs when two solid objects touch each other. If they are not moving, it is called static friction. If they are moving, it is called kinetic or sliding friction. 2  Fluid Friction - Fluid friction involves a fluid or air.