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Which force resists motion between objects that are in contact?

Friction resists the motion between objects that are in contact with each other. There are two types of frictional forces: static friction and kinetic friction. Static friction is the frictional force that is applicable for bodies at rest and it resists the motion between two bodies that are in contact and are at rest. Kinetic friction, on the other hand, is the frictional force that is applicable for bodies in motion. Kinetic friction opposes the relative motion of bodies that are in contact and are in motion.


Think about what happens when we gently push a book over the surface of a table. It stops after traveling some distance. The book stops due to the frictional force, which resists the motion. 


Friction between two surfaces can be reduced by making the surfaces smooth. Applying grease is an example of a way to lessen friction.


Hope this helps. 

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