Question

List - I	List - II
a) Static friction	e) constant for a given pair of surfaces.
b) Limiting friction	f) independent of area of contact
c) Kinetic friction	g) self adjusting
d) Rolling friction	h) has least magnitude for given normal reaction.

• A. a-e;b- f ;c-g;d -h
• B. a-h;b-f ;c-e;d-g
• C. a-g ;b-e;c-f ;d -h
• D. a-g ;b-h;c-f ;d-e

Answer 1

The correct option is C a-g ;b-e;c-f ;d -h

a) Static friction is an adjusting force. Two bodies in contact have this varying force which tries to resist the sliding between two bodies. Its value is equal to the net external force on the object that tends to cause sliding.

b) Limiting friction is the maximum amount of static friction that can act between two surface. It is a property of the given pair of surfaces in contact.

c) Kinetic friction is the constant friction acting between two surface when sliding upon each other. It depends upon the normal reaction between the surfaces and is independent of the area of contact.

d) Rolling friction is the friction acting on a rolling body to resist the motion. It has least magnitude compared to other cases with same normal reaction. It can sometimes be zero even.