Question

how is friction defined?
a.) friction resists the motion of objects but only exists on visibly rough surfaces
b.) friction is a non - contact force that resists motion of objects
c.) friction is a force of resistance acting between objects in contact and tending to slow or stop their motion

Explanation:

Friction is a contact force. It acts between objects in contact. Its main effect is to resist or oppose the relative motion between those objects. Option a is wrong because friction exists on all surfaces (even smooth - looking ones have microscopic irregularities). Option b is wrong as friction is a contact force. Option c correctly describes friction as a resistance force between contacting objects that slows or stops motion.

Answer:

C. Friction is a force of resistance acting between objects in contact and tending to slow or stop their motion