devarshi-dt-logo

Question:

Alida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be

Wet marble floor, dry marble floor, newspaper and towel.

Newspaper, towel, dry marble floor, wet marble floor.

Towel, newspaper, dry marble floor, wet marble floor.

Wet marble floor, dry marble floor, towel, newspaper.

Solution:

The correct option is A Wet marble floor, dry marble floor, newspaper and towel.
The nature of the surfaces in contacts decides the friction force between them. The friction force will be more if the surfaces in contact are rougher. Among the following the wet marble floor is least rough therefore least friction force. Then the increasing order of roughness is dry marble floor, newspaper and most rough is towel. Therefore the friction force will also be in same order.