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NCERT Solutions for Class 8 Science Chapter 9 - Friction

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NCERT Solutions for Class 8 Science Chapter 9 Friction - Free PDF Download

Class 8 Science Friction is an important chapter that provides students with a solid understanding of the forces that oppose motion. Friction Class 8 is a fundamental concept in physics that affects everyday life in various ways. In Class 8 Science Chapter 9 Question Answer, you'll delve into the nature of friction, its types, and its effects on different surfaces.

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Table of Content
1. NCERT Solutions for Class 8 Science Chapter 9 Friction - Free PDF Download
2. Glance on NCERT  Solutions for Class 8 Science Chapter 9 Friction
3. Access NCERT Solutions for Class 8 Science Chapter 9 – Friction
4. Class 8 Science Chapter 9 Friction - Quick Overview of Topics Covered
5. Class 8 Science Chapter 9 - Friction- Important Points
6. Benefits of Vedantu’s Class 8 Science Chapter 9 Friction Question Answers
7. Important Study Material Links for Class 8 Science Chapter 9 Friction
8. NCERT Solutions for Class 8 Science - Chapter-wise Links
9. Other Important Links for Class 8 Science
FAQs


Vedantu’s NCERT Solutions for Class 8 Science Chapter Friction offers comprehensive solutions to all the questions in this chapter, facilitating a smoother learning process. The Friction Class 8 Solutions are prepared by Vedantu’s Master Teachers that help you grasp the important concepts of this topic. Download the FREE PDF of Class 8 Science Chapter 2 Question Answer, updated according to the CBSE Class 8 Science syllabus. Start learning with Vedantu and achieve academic success!

Glance on NCERT  Solutions for Class 8 Science Chapter 9 Friction

  • Class 8 Science Chapter Friction Question Answer provides a comprehensive understanding of friction, its types, and the factors influencing it. 

  • Friction Class 8 PDF delves into the concept of friction as a force that opposes motion, explaining its significance in everyday life and various technological applications. 

  • Class 8 Science Chapter 9 discusses the different types of friction, including static, sliding, and rolling friction, and explores the conditions under which each type occurs.

  • Detailed explanations are provided on the methods of increasing and reducing friction, highlighting the practical uses and challenges associated with these adjustments in real-world scenarios.

  • Utilising these NCERT Class 8 Science Chapter 9 Question Answer can help students evaluate their grasp of friction, enhance their problem-solving skills, and prepare effectively for exams.

Access NCERT Solutions for Class 8 Science Chapter 9 – Friction

1. Fill in the blanks
  • Friction opposes the ________ between the surfaces in contact with each other.

Ans: Motion

  • Friction depends on the _________ of surfaces.

Ans: Nature

  • Friction produces _________. 

Ans: Heat

  • Sprinkling of powder on the carrom board ________ friction.

Ans: Reduce

  • Sliding friction is ________ than the static friction.

Ans: Lesser


2. 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.
    1. rolling, static, sliding

  1. rolling, sliding, static

  2.  static, sliding, rolling

  3.  sliding, static, rolling

Ans: (c) Static, sliding, rolling.

Static Friction: When we move an object which is at rest. 

Sliding Friction: Acts on a body when it is moving. 

Rolling Friction: Here the area of contact is smallest when compared to static and sliding friction. 


3. 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 and 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

Ans : (a) Wet marble floor, dry marble floor, newspaper and towel.

Friction will be more if the surface is rough and it will be less if the surface is smooth. Hence, wet marble floor, dry marble floor, newspaper and towel is the correct sequence of these surfaces when arranged according to the increase in the force of friction acting on the car.


4. 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.

Ans: When a book slides down a table, frictional force always acts always opposite to the direction of motion and along the incline.

Force of friction will always be parallel to the surfaces in contact.


Friction Forcr


5. 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?

Ans: It would be difficult to walk on the floor when soapy water falls on the floor then the friction reduces therefore the chances to slip increases, as a result it becomes difficult to walk. 

When there is no soapy water then there will be interlocking between the foot and the ground.

When soap water spills the interlocking gets spoilt as a result friction reduces.


6. Explain why sportsmen use shoes with spikes.

Ans: Spikes present on the shoes make the surface of the shoes rough. This increases the friction. As friction increases, the grip on the ground increases. This makes it easier for them to walk or run.


7. Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?

Ans:

  • Friction is directly proportional to mass. Heavier an object more force to be applied to move it.

  • Heavier box will press the floor surface harder as compared to the lighter box.

  • The two surfaces are pressed harder against each other, so the force required to overcome the interlocking is more in case of the heavier box.

  • So Seema has to apply more force as compared to Iqbal.


8. Explain why sliding friction is less than static friction.

Ans: During sliding, contact points do not get enough time to get interlocked properly. Friction forces come into play when irregularities present in the surface of the two objects in contact get interlocked with each other. When an object is in motion, the sliding friction is smaller than the static friction as the interlocking during motion is very small. Thus, sliding friction is less than static friction.


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

Ans:

Friction is a friend in the below ways:

  • It helps us to walk.

  • It helps us to hold things.

  • It helps in grinding.

  • It helps in construction purposes.

  • It makes matchstick ignition possible.

Friction as a foe in the below ways:

  • It opposes motion.

  • It produces a lot of heat which results in wastage of energy.

  • It brings about wear and tear of machinery parts.

  • It leads to the application of more power in machines.

  • It produces noise in the machines.


10. Explain why objects moving in fluids must have special shapes.

Ans: Special shapes experience less fluid friction therefore can move easily through fluids. When an object moves in fluid, fluid friction opposes the motion. So, to reduce the friction between object and fluids, the object is given a special shape known as streamlined shape.

An aeroplane is a good example for this. The air exerts some friction when the aeroplane moves through the air. This will be opposed by the motion of the aeroplane. In order to overcome this friction, the aeroplane has to apply a lot of force. This force is in turn a waste of energy. So, it is necessary to design the shape of the aeroplane in such a way that it experiences less fluid friction.


Class 8 Science Chapter 9 Friction - Quick Overview of Topics Covered

S.No.

Topics of Friction Class 8

1.

Force of Friction

2.

Factors affecting Friction

3.

Friction: A Necessary Evil

4.

Increasing and Reducing Friction 

5.

Wheels Reduce Friction

6.

Fluid Friction


Class 8 Science Chapter 9 - Friction- Important Points

  • Friction is a force that opposes the relative motion between two surfaces in contact.

  • Types of Friction:

    • Static Friction: The friction that acts on objects when they are not moving.

    • Sliding Friction: The friction that occurs when one object slides over another.

    • Rolling Friction: The friction that occurs when an object rolls over a surface.

    • Fluid Friction: The resistance experienced by objects moving through a fluid (liquid or gas).

  • Factors Affecting Friction:

    • Nature of Surfaces: Rough surfaces have more friction compared to smooth surfaces.

    • Normal Force: The force exerted by a surface perpendicular to the object. The greater normal force increases friction.

    • Contact Area: Larger contact areas can increase friction.

  • Advantages of Friction:

    • Enables walking without slipping.

    • Helps in writing by providing a grip to the pen or pencil.

    • Essential for the functioning of various machines and tools.

  • Disadvantages of Friction:

    • Causes wear and tear of moving parts in machinery.

    • Leads to energy loss in the form of heat.

    • Reduces efficiency of machines.

  • Methods to Reduce Friction:

    • Lubrication: Applying lubricants like oil or grease to surfaces.

    • Use of Ball Bearings: Reduces rolling friction in machines.

    • Streamlining: Designing objects to reduce fluid friction.


Benefits of Vedantu’s Class 8 Science Chapter 9 Friction Question Answers

  • Vedantu’s NCERT Class 8 Science Chapter 9 Question Answer offers comprehensive explanations of key concepts such as the nature of friction, its causes, types, and effects, providing a thorough understanding of this fundamental force in physics.

  • Class 8 Science Chapter 9 Friction Question Answers provide detailed and step-by-step solutions to clarify complex concepts involved in frictional forces, enhancing comprehension and retention.

  • Class 8 Science Chapter 9 Question Answer includes diagrams and illustrations that make learning about different types of friction more visual and easier to grasp.

  • Class 8 Science Chapter Friction Question Answer are aligned with the NCERT textbook, ensuring they cover all topics in the syllabus and follow the CBSE curriculum.

  • Class 8 Science Friction PDFs are prepared to help students in exam preparation by providing practice questions and answers.

  • Vedantu also offers additional study materials such as class notes, important concepts, and exemplar solutions to reinforce learning and ensure a solid grasp of the subject matter.


Important Study Material Links for Class 8 Science Chapter 9 Friction

S.No.

Important Study Material Links for Class 8 Science Chapter 9

1

Class 8 Friction Important Questions

2

Class 8 Friction Revision Notes

3

Class 8 Friction Exemplar Solutions



Conclusion

Vedantu’s Friction Class 8 NCERT PDF Questions and Answers offer a helpful guide for students to understand the concept of friction easily. The solutions provide clear explanations and step-by-step answers, aiding in grasping important concepts related to friction. Students must focus on understanding the factors affecting friction, its types, and practical applications in everyday life. Previous year question papers have typically included around 5–7  questions from this chapter, emphasizing the importance of thorough preparation. By utilizing Vedantu’s solutions, students can enhance their understanding, improve problem-solving skills, and achieve success in their examinations.


NCERT Solutions for Class 8 Science - Chapter-wise Links


Other Important Links for Class 8 Science

FAQs on NCERT Solutions for Class 8 Science Chapter 9 - Friction

1. Explain the Concept of Sliding Friction and its Relation to the Mechanism of Static Friction.

Frictional forces play a key role when irregularities on the surface of an object are discovered even if the surface is smooth. This is observed when the irregularities of two surfaces come into contact with each other and get interlocked. Sliding friction or kinetic friction is a contact force that resists the sliding motion of two objects. Static friction is the force of friction observed on a stationary object. It is larger than sliding friction as the interlocking mechanism is very small.

2. What are Some Examples of Friction Observed in Our Daily Lives?

Friction is both a friend and a foe. Some instances where we see friction in action are as follows:

  • Walking or running up or down a hill.

  • The wear and tear of shoes after vigorous activity.

  • The contact between the pen and the paper and the motion of the pen while writing.

  • The damages are caused by continuous exposure to heat in heavy-duty machines as they are continuously run. Therefore, lubricants are used to decrease the wear and tear of these machines.

  • Rubbing our hands together to generate heat

3. What are the various types of friction? Explain.

There are four types of Friction:

  • Static Friction - The frictional force, which acts in between two surfaces, when both are at rest with respect to each other.

  • Sliding Friction - The frictional force acts between two surfaces that are sliding with respect to each other.

  • Rolling Friction - The resisting force acts between the motion of anybody that performs rolling motion.

  • Fluid Friction - When the frictional force acts between two layers of liquid flowing with respect to each other.

4. What is the cause of friction?

A surface is not completely smooth and always has some irregularities, which become the main cause of the force of friction that comes into play when two surfaces come in contact with each other. If we go into the details, the roughness of the surface and molecular adhesion of surface molecules are the main reason behind the friction of any surface. So, the surfaces which have more roughness tend to have more friction.

5. What is friction?

The force which is resistive in nature and comes into play due to the relative motion between two surfaces is known as friction. The direction of the force is always opposite to the direction of motion and it tends to oppose the motion of the body. It comes into play due to the irregularities in surfaces and molecular adhesion properties of the surfaces of the objects. It is mainly of 4 types.

6. List out the topics included in Chapter 9 of NCERT Solutions for Class 8 Science.

Following are the topics included in Chapter 9 of NCERT Solutions for Class 8 Science:

  • Force of Friction

It has one short answer

  • Factors affecting friction

It has two MCQs and one short answer

Friction: A Necessary Evil

It has one long answer

  • Increasing and Reducing Friction

It has one short and one long answer

  • Wheels Reduce Friction

It has one short answer

  • Fluid Friction

It has two MCQs and one short answer 

Students can download the PDF file of NCERT Solutions free of cost to study offline.

7. What is frictional force covered in Chapter 9 of NCERT Solutions for Class 8 Science?

The frictional force is the force that acts between two surfaces when there occurs any relative motion between them. It resists the motion between the surfaces. It is caused due to irregularities in the surface and the adhesion of molecules of one surface with another. The force of friction is also necessary for the motion and thus is also known as a necessary evil.  There are four types of frictional forces, static, sliding, rolling and fluid. To know more about Chapter 9 Class 8 Science, visit the Vedantu app and the website (vedantu.com).

8. How can NCERT Solutions for Class 8 Science Chapter 9 help in understanding friction?

Friction Class 8 Solutions provide comprehensive explanations, detailed answers, diagrams, and illustrations, which help in understanding the concepts of friction better. Friction Class 8 PDF offers step-by-step solutions to questions, making it easier for students to grasp the topic effectively.

9. How does friction affect the performance of vehicles?

Friction between the tires of a vehicle and the road surface provides the necessary grip for acceleration, braking, and turning. However, too much friction can also lead to wear on tires and increased fuel consumption.