Question

Hoe to determine whether surface is smooth or rough?

Answer 1

In reality no smooth surface exist as it is not possible having the coefficient of Friction zero. Every object has a somewhat rough surface which causes Friction. In numericals the coefficient of friction is mentioned, if there coefficient of friction is zero then we have to consider the surface to be smooth with no friction acting on it, whereas if the coefficient of friction is more than zero then the surface is considered as rough which opposes the applied force.

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hope this helped :)

Answer 2

Answer:

Surface roughness often shortened to roughness, is a component of surface texture. It is quantified by the deviations in the direction of the normal vector of a real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smooth.