Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.

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

The force of friction always

Friction is due to

Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play

It is difficult to walk on a wall polished floor because friction between our feet and floor is

If we apply oil on door hinges, the friction will

Fine powder is poured on the carromboard to

Rolling friction is smaller than

A boy rolls a rubber ball on a wooden surface. The ball travels a short distance before coming to rest. To make the same, ball travel longer distance before coming to rest, he may

Static friction is ________ than the sliding friction.

Ball bearings reduce friction because they rolls rather than ___________

All objects moving in fluids have ________ shape to reduce friction.

The substances are used in machines to protect their surfaces from wear and tear caused by ___________ are called lubricants.

We pour a drop of oil on the hinge of door to __________ friction.

The pieces of luggage fitted with the rollers. Explain why.

Is frictional force a contact force?

Why it is difficult to move on a wet marble floor?

Why are oil, creams and grease called lubricants?

Can we eliminate friction completely?

Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.

You spill a bucket of soapy water on a marble floor accidentally. Would it make it easier or more difficult for you to walk on the floor? Why?

Give examples to show that friction is both a friend and a foe.

You might have noticed that when used for a long time, slippers with rubber soles become slippery. Explain the reason.

Name any of the five smooth surfaces from your surroundings.

We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason.

In physics classroom a teacher told to his students that when a cricket player want to catch a ball then first he rub the hands. Thus, there is less chance of slipping the ball from hands. 
(a) Explain the reason of not slipping of ball from hand
(b) If the player makes his hands oily instead of rubbing them. Would he be able to catch the ball?
(c) Mention the type of teaching skills of teacher is being represented here?