Answers

2015-07-29T13:52:04+05:30
The cause of friction is the irregularities of the surface on which the mass ( body ) moves. Friction force always opposes motion i.e. if an object is moving to the right, friction force will act to the left.
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you copied from anouther site right
The same definition was also given by my teacher. Don't know from where.
sorry
Its OK !!