question_answer

Force of friction is ____i____   for a rough surface. Spilling oil on a surface ____ii_____    friction. The information in which alternative completes the given statements?

Answer:

(d) Friction opposes the relative motion between two surfaces in contact. It depends on the nature of surfaces in contact. The force of friction is more when the irregularity present between the two surfaces is large. Oil is a good lubricant. Application of oil on a surface increases the smoothness of the surface and decreases its roughness. The friction of a surface decreases when oil is applied on it. The correct answer is D.