Question

Driving a car on a wet road is difficult because water –
A) Makes it difficult to turn the car
B) Decreases the friction between the tyres and the road.
C) Increases the friction between the tyres.
D) Makes friction between the road and tyres zero.

Answer 1

Hint: We need to understand the role of water that creates the difficulty in driving during a wet season on a road. The water has to be either a lubricant type substance or a roughening substance in order to create this extra difficulty while driving.

Complete Solution:
Roads are surfaces which provide necessary friction for smooth rolling of tyres for a safe journey. The roads are constructed such that the friction is enough to roll the tyres without skidding – in case of lower friction – or without tripping – in case of larger friction.

The rubberized roads have made the travel so smooth that the risk of skidding when taking turns or braking cannot be avoided. The situation is worse during the wet seasons. The water on the roads act as a lubricating agent which lowers the frictional coefficient between the tyre and the road. A car which could travel smoothly at 30 \[m{{s}^{-1}},\] during the dry seasons will skid during a wet season. This is due to the water reducing the friction between the surfaces which reduces the rolling ability and thus provokes skidding with the force applied by the car engine.

So, driving on a wet road is difficult because water reduces the friction between the tyres and the road.

Hence, the correct answer is option B.

Note:
We should always keep in mind that the reduction of friction is only to a very minimal level. The decrease will never go down to zero because then the driving or even walking will not be possible at such a surface, an example will be ice which has almost zero friction.