RRB NTPC · Question 22

Which of the following is NOT true about Frictional force? A. Friction is the force that 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.

1. A

   D

2. B

   A

3. C

   C

4. D

   B