Question

friction or frictional force are same

Answer 1

FRICTION IS A CAUSE THAT OPPOSES ANY RELATIVE MOTION BETWEEN TWO SURFACE IN. CONTACT .
THE FRICTIONAL FORCE DIRECTLY DEPENDS ON THE NORMAL RELATION BETWEEN THE TWO SURFACE IN CONTACT . SO, FRICTION IS A CAUSE OF OPPOSITION

Answer 2

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The force that always opposes the relative motion between two surfaces in contact . The force of friction acts in the direction opposite to the direction in which an object moves.