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Creative questions were added in this question paper in order to enhance the student's knowledge and get the idea that how to answer strategic questions asked in the board exams. This question paper is designed based on the academic syllabus. Sample papers should be practiced in examination condition at home or school and also show it to your teachers for checking or compare with the answers provided.

From the post, the questions are covered from the chapter Friction and questions are prepared from creative like NCERT and HOTs as well as previous year questions.

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Questions:

Fill up / 1 Marks

5 x 1 = 5

The soles of our shoes get worn out after a period of time. It is due to ___________

Cars and speedboats are _______ to reduce drag.

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

________ is produced by friction.

Friction produces _________

Multiple Choice Question

5 x 1 = 5

The fishes swim easily in the water because they have

(a)

more energy

(b)

streamlined shape

(c)

Both (a) and (b)

(d)

None of these

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

(a)

spread a carpet on the wooden surface

(b)

cover the ball with a piece of cloth

(c)

sprinkle talcum powder on the wooden surface

(d)

sprinkle sand on the wooden surface

Fine powder is poured on the carromboard to

(a)

increase friction

(b)

decrease friction

(c)

Both (a) and (b)

(d)

None of these

To sharpen the blade of a knife by rubbing it against a surface, which of the following will be most suitable?

(a)

Stone

(b)

Plastic block

(c)

Wooden block

(d)

Glass block

10.

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

(a)

wet marble floor, dry marble floor, newspaper, towel

(b)

newspaper, towel, dry marble floor, wet marble floor

(c)

towel, newspaper, dry marble floor, wet marble floor

(d)

Wet marble floor, dry marble floor, towel, newspaper

Generic 3

4 x 3 = 12

11.

Why is it easy to drag a mat when nobody is sitting on it but difficult when somebody is sitting on it?

12.

Two boys are riding their bicycles on the same concrete road. One has new tyres on his bicycle while the other has tyres that are old and used. Which of them is more likely to slip while moving through a patch of the road which has lubricating oil spilled over it?

13.

Is there a force of friction between the wheels of a moving train and iron rails? If yes, name the type of friction. If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?

14.

Explain why sliding friction is less than the static friction.

Generic 2

5 x 2 = 10

15.

Name two methods of reducing friction with examples.

16.

What do you mean by lubricants?

17.

Liquids and gases are called as fluid. Why?

18.

Explain fluid friction in brief.

19.

Name the force helps to writs ty chalk on blackboard.

Generic 5

2 x 5 = 10

20.

Discuss the various ways to reduce the friction.

21.

Explain some examples where we have to reduce the friction.

1 Marks

5 x 1 = 5

22.

Can we reduce friction to zero?

23.

What makes it difficult to walk on wet floor?

24.

Name the friction that is overcome by most machines by the use of ball bearings. Name the type of friction with which it is replaced.

25.

Name the friction when wheels are used to carry heavy weights.

26.

Name the force that always opposes the applied force.

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Answers Key:

Fill up / 1 Marks

5 x 1 = 5

()
friction

()
streamlined

()
reduce

()
Heat

()
heat

Multiple Choice Question

5 x 1 = 5

(b)
streamlined shape

(b)
decrease friction

(a)
Stone

10.

The correct arrangement is as follows: Wet marble floor, dry marble floor, newspaper, towel.

Generic 3

4 x 3 = 12

11.

We know that friction is caused by the interlocking of the irregularities in the two surfaces. It is obvious that the force of friction will increase if the two surfaces are pressed harder. So it is easy to drag a mat when nobody is sitting on but difficult when someone is sitting on it but difficult when someone is sitting on it.

12.

The boy having the tyres which are old and used is most likely to slip because these tyres will experience less frictional force which is insufficient to move on the oily road.

13.

Yes, there is always a force of friction between the wheels of a moving train and iron rails. The name of this friction is rolling friction, since, the wheels are rolling on the track. On introducing air cushion, the frictional force becomes less, since there is no contact between rails and wheels.

14.

We know that friction is caused by the interlocking of irregularities in the two surfaces. In case of static friction, interlocking between two objects is very strong but in case of sliding friction, there is a less time of getting interlocked with each other. Thus, the sliding friction is less than the static friction.

Generic 2

5 x 2 = 10

15.

(i) Rolling: The rolling wheels attached to luggage bags make it comfortable for passengers to carry them because rolling reduces friction and is smaller than sliding friction.
(ii) Sliding: By polishing surfaces or by applying a lubricant.

16.

The substances which reduce friction are called lubricants e.g., oil creams and grease.

17.

Liquids and gases can flow and they do not have definite shape. So, they are called as fluid.

18.

When an object moves in a fluid, then the resistance to the movement of object exerted by fluid is called fluid friction.

19.

Frictional force helps to write by chalk on blackboard.

Generic 5

2 x 5 = 10

20.

Friction may be reduced in the following ways:
(i) Polishing the surface: We polish the rubbing surfaces to reduce their unevenness and make them smooth.
(ii) Lubricating the surface: To reduce friction in order to increase efficiency when oil, grease or graphite is applied between the moving parts of a machine, a thin layer is formed there and moving surfaces do not directly rub against each other. These substances are lubricants which reduce the friction.
(iii) Using wheels and ball bearings: By using wheels and ball bearing we convert sliding friction into rolling friction. This reduces friction between the two contact surfaces and helps us to save energy, effort and time.
(iv) Streamlining: Objects are given special shapes, such as streamlined body to aeroplanes. Their bodies shapes make them lose less energy in overcoming friction. Hence, all vehicles are designed to have shapes that reduce fluid friction.

21.

When a fine powder sprinkled on the carrom board and a few drops of oil are poured on the hinges of a door, the door moves smoothly. A cycJe or a motor mechanic some times uses grease between the moving parts of the cycle. In all the above cases, our try was to reduce friction in order to increase efficiency.
Also, interlocking of irregularities is avoided to a great extent due to which the movement becomes smooth. The substances which reduce friction are called lubricants. In some machines, it may not be advisable to use oil as lubricant. There is an air cushion between the moving parts, that is used to reduce friction.

1 Marks

5 x 1 = 5

22.