Question

Friction is a type of a __________ force which opposes the__________ between two surfaces.

• A. non-contact, relative motion
• B. contact, relative motion
• C. non-contact, pressing force
• D. contact, pressing force

Answer 1

The correct option is B contact, relative motion

A force which can be exerted by an object on another object only when they are physically touching is called a contact force.
Friction is an example of contact force.
Frictional force is an opposing force which acts between two surfaces in contact, when there is relative motion between them.