How does banking of roadsreduce wear and tear of the tyres ?

How does banking of roads reduce wear and tear of the tyres ?

A : Banking of roads reduces the wear and tear of the tyres of automobiles. R : By banking of the roads one component of the normal reaction on the automobile contributes to necessary centripetal force.

Assertion : Improper banking of roads causes wear and tear of tyres. Reason : The necessary centripetal force is provided by the force of friction between the tyres and the road.

Banking of roads at curve is necessary so as to avoid (A) overturning of vehicle moving with maximum speed (B) the dependence of centripetal force on the force of friction (c) rough nature of road surface which increases the force of friction and causes the wear and tear of tyres of vehicle . (D) skidding of the vehicle. the correct statements is /are

A circular racetrack of radius 100 m is blanked at an angle of 45 ^(@) . What is the (i) Optimum speed of race car to acoid wear and tear of its tyres ? (ii) Maximum permissible speed to acoid slipping if the coefficient of friction is 0*22 ?

A circular racetrack of radius 300 m is banked at an angle of 15^(@) If the coefficient of friction between the wheels of a race car and the road is 0.2 what is the (a) optimum speed of the race car to avoid wear and tear on its tyres , and (b) maximum permissible speed to aviod slipping ?