Question

On one hand you say that when two smooth, even surfaces slide over each other, there is adhesion between them which causes friction. On the other you say that there is no friction between two smooth surfaces. I'm not getting.

Mark the word SMOOTH.

Answer 1

First of all...friction cannot be completely eradicated,how ever the SMOOTH the surface is,there willbe friction due to adhesive force and also very small iregulariteies between smooth surface......
Smooth surface cannot make zero friction rather it reduce friction to some extent


And some time its say..there is no friction in smooth surface.it is said in problems to make the problem easy.if we take friction into consideration ,problem become more difficult.so its is considere ther is no friction between smooth surface

Note:actually friction exist between smooth surface