Sliding friction is a force that opposes the motion of two surfaces sliding past each other. It is caused by the irregularities and roughness of the surfaces in contact. When an object is in motion on a surface, the irregularities on the surfaces interlock and create resistance to the motion, resulting in sliding friction.
The student demonstrates an understanding of the interactions between matter and energy and the effects of these interactions on systems by researching applications of nuclear reactions in which a small amount of matter is converted directly into a huge amount of energy (i.e., E=MC2). (L)