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.
Table of Content
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.
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
rolling, static, sliding
rolling, sliding, static
static, sliding, rolling
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
Important Study Material Links for Class 8 Science Chapter 9 Friction
NCERT Solutions for Class 8 Science - Chapter-wise Links
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FAQs on NCERT Solutions for Class 8 Science Chapter 9 Friction
1. How do the NCERT Solutions for Class 8 Science Chapter 9 define friction?
As per the NCERT Solutions for the 2025-26 session, friction is defined as a force that opposes the relative motion between two surfaces in contact. It always acts in the direction opposite to the direction of the intended or actual movement.
2. What are the main types of friction explained in the Class 8 Science Chapter 9 solutions?
The NCERT Solutions for Chapter 9 categorise friction into three main types, which must be understood in the correct order of magnitude:
- Static Friction: The force that must be overcome to start moving an object from a state of rest. It is the strongest type.
- Sliding Friction: The force that opposes motion when one surface slides over another. It is less than static friction.
- Rolling Friction: The force that opposes motion when an object rolls over a surface. It is the weakest of the three.
3. What is the step-by-step method to solve the NCERT question about arranging surfaces in increasing order of friction?
To solve this problem as per the CBSE guidelines, follow these steps:
- Step 1: Understand the core principle that friction increases with the roughness of the surface.
- Step 2: Analyse the given surfaces (e.g., wet marble floor, dry marble floor, newspaper, towel).
- Step 3: Rank the surfaces from smoothest to roughest. A wet surface provides lubrication, making it smoothest. A towel has a very rough texture.
- Step 4: State the final order. The correct sequence for increasing friction is: wet marble floor < dry marble floor < newspaper < towel.
4. Why do the NCERT solutions state that sliding friction is less than static friction?
The solutions explain that static friction is greater because when an object is at rest, the microscopic irregularities on the two surfaces have sufficient time to deeply interlock with each other. To start motion, a significant force is needed to break this lock. Once the object is sliding, the contact points move past each other so quickly that they don't get enough time to form strong interlocks, resulting in a smaller opposing force (sliding friction).
5. How do the solutions for Chapter 9 explain why athletes wear shoes with spikes?
The NCERT solutions explain that athletes wear shoes with spikes to increase friction. The spikes press into the ground, creating a much stronger grip and better interlocking between the shoe and the surface. This increased friction prevents slipping and allows the athlete to push off the ground with greater force, which is essential for running and other sports activities.
6. According to the NCERT solutions, why is it more difficult to push a heavier box than a lighter one?
The solutions clarify that a heavier box exerts a greater force on the floor. This increased force presses the two surfaces together more firmly. As a result, the interlocking of surface irregularities becomes much stronger. To overcome this enhanced interlocking, a larger force must be applied. Therefore, the force of static friction is greater for the heavier box.
7. How are problems related to 'fluid friction' solved in Class 8 Science Chapter 9?
Problems on fluid friction in the NCERT solutions are solved by understanding that fluids (liquids and gases) exert a frictional force called drag. The solution to reducing drag is to use a streamlined shape. This special shape, seen in fish, birds, and aeroplanes, allows the fluid to flow smoothly around the object, minimising resistance and making movement through the fluid easier.
8. Why is friction called a 'necessary evil' in the Class 8 NCERT solutions?
Friction is termed a 'necessary evil' because it has both beneficial and harmful effects. It is necessary for essential activities like walking, writing, and applying brakes. However, it is also an evil because it opposes motion, causes wear and tear of machinery parts, and wastes energy by converting it into unwanted heat, thus reducing efficiency.
9. What is the correct method described in the solutions for reducing friction?
The NCERT solutions for Chapter 9 outline several effective methods to reduce friction:
- Lubrication: Applying substances like oil or grease forms a thin layer between surfaces, preventing direct contact and reducing interlocking.
- Polishing: Making surfaces smoother reduces the number and depth of irregularities.
- Using Ball Bearings: These devices convert less efficient sliding friction into more efficient rolling friction, which is significantly lower.
10. How do the NCERT solutions explain the effect of friction on the efficiency of machines?
The solutions explain that friction negatively impacts machine efficiency in two primary ways. Firstly, it opposes the motion of moving parts, meaning that some of the input energy is wasted in overcoming this frictional force instead of doing useful work. Secondly, this wasted energy is often converted into heat, which can damage machine components and represents a significant energy loss.
