Which of the following is not true about Frictional force?_x005F_x000D_

• A. Friction is the force which opposes the relative motion of two surfaces in contact
• B. The force of friction that acts when a body is moving (sliding) on a surface is called sliding friction
• C. Friction in machines wastes energy and also causes wear and tear
• D. Rolling friction is much more than sliding friction, the use of ball bearings in a machine considerably reduces friction