Question

Why are vehicle tyres treaded
(A) To increase friction
(B) To decrease friction
(C) To multiply friction
(D) To decrease grip

Answer 1

Hint The friction between two objects is directly related to the degree of roughness of the surfaces in contact. Tyres are treaded to increase the roughness of the tyres.
Formula used: In this solution we will be using the following formulae;
 $ F = ma $ where $ F $ is force, $ m $ is mass and $ a $ is acceleration of the object.

Complete step by step answer
As it is well known to us, friction is defined as a force which opposes motion. However this same ability to oppose motion is also what allows controlled motion, that is to say, without the existence of friction, all bodies will be set in motion forever even at the slightest displacement from rest by a force, and would be extremely difficult to bring to rest as it would require a perfectly balanced force from all sides (which is difficult to achieve). Hence, the increase in friction can sometimes be beneficial.
Friction in general is said to be proportional to the degree of roughness of the surfaces in contact. Roughness is characterised by the undulation of terrain of a surface i.e. the degree of up and down present in the surface. A surface is rough as long as it has such undulating terrain irrespective of whether it is scattered and unstructured or arranged and intelligently designed.
Hence, from these we can conclude that a tyre is treated to increase the grip thus increasing the friction between the tyres and the road.
Hence, the correct option is A.

Note
To avoid confusion, the force creates a never ending motion because since $ F = ma $ , then the slightest force $ F $ creates an acceleration $ a = \dfrac{F}{m} $ which is non zero however minuscule the force may be. Now due to the inertia of motion, these bodies will tend to remain in motion even after the force has been released. Thus without friction to act on it to stop the motion, it will continue to be forever in motion.