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# NCERT Exemplar Class 8 Science Chapter 12 Solutions: Friction

NCERT Exemplar Class 8 Science Solutions Chapter 12 ‘Friction’ has been written keeping in mind your homework and revision requirements in the exam time. This is an interesting chapter of NCERT Exemplar Class 8 Science covering the contact force of friction, factors that affect friction, how friction is an essential and negative force, how we can reduce or increase the force of friction according to our convenience, and fluid friction. You will come across terms such as rolling friction and sliding friction while solving the NCERT Exemplar problems of Friction.

In Exemplar Chapter 12 of Class 8 Science, a total of 25 questions are given in the exemplar exercise covering all the topics of Friction in a detailed manner. These questions are arranged in increasing order of difficulty level. You will be required to state true or false, complete the sentences by filling in the blanks, matching the correct pair of options. These exercise questions will help you prepare extensively for an inter-school science quiz, olympiads, and the NTSE exam.

The solutions provided at Instasolv are written consciously in a very simple language to help understand the core concepts related to friction. These solutions are prepared by experienced science faculties who are aware of the commonly occurring doubts of each topic. You should practice these exemplar questions by referring to the answers given at Instasolv.

## Important Topics for NCERT Exemplar Class 8 Science Solutions Chapter 12 – Friction

Introduction to Friction

The force of friction is a resistance force that occurs between surfaces of the objects undergoing motion with respect to one another.

The force of friction always acts against the direction of the motion.

Factors that Effect Friction

1. The force of friction is caused by the innumerable minute irregularities on the surface of the two objects which are in contact.
2. The greater is the irregularity on a surface, the greater is the friction and amount of interlocking between the two objects. Hence, it will require greater force to result in motion.
3. Static friction is the amount of force required to bring an object in motion from its state of rest.
4. Sliding friction is the amount of force required to make the object move at the same speed as earlier.

Friction: Essential and Evil

1. Friction is essential to make the brakes of an automobile function, or the chalk to be effective against a blackboard. It is also important to enable us to walk.
2. Friction is also an evil, as it is the reason for wearing off the shoes of the brakes, sole of our shoes, steps of foot over-bridges, etc. Friction also leads to wastage of energy in many cases.

Increasing and Reducing Friction

1. We increase friction by cutting grooves in our shoes, using treaded tires in vehicles, and brake pads in vehicles, etc. Therefore, we can increase friction by increasing irregularities on the surface.
2. We can decrease friction by minimizing the irregularities on the surface using lubricants by greasing the surfaces.
3. Wheels also reduce friction since rolling friction is smaller than the sliding friction. It can be applied using ball bearing in many machines.

Fluid Friction

1. Gases and liquids are together called fluids. The friction exerted by the fluids is also termed as drag.
2. Friction by a fluid depends upon the speed of the object and fluid, the shape of the object, and the nature of the fluid.

## Exercise Discussion of the NCERT Exemplar Class 8 Science Chapter 12 – Friction

1. There are 8 multiple-choice questions in the NCERT Exemplar exercises. These questions will require you to have a deep conceptual understanding of friction in the physical sciences.
2. The very short answer questions comprise problems with one-word answers and are based on situational questions related to friction and factors affecting friction.
3. The questions in the third section are of short answer type reasoning problems. These questions have covered the topics of rolling friction and sliding friction thoroughly.
4. There are 4 long answer exercise questions in the science exemplar chapter 12. These are mostly elaborate questions where you will be required to list the reason for the occurrence of certain situations.

## Why Use NCERT Exemplar Class 8 Science Problems with Solutions for Chapter 12 by Instasolv?

1. Solving the questions of NCERT Exemplar Class 8 Science Chapter 12 at Instasolv will help you develop an aptitude to approach the problems of physics easily.
2. Each question is covered with in-depth analysis and is in line with the updated CBSE guidelines.
3. You will get ample opportunity to clear your queries at the interactive Instasolv platform.
4. At Instasolv, you can make your self-study hours very efficient.
5. This source of reference by Instasolv is an excellent brush up for your CBSE school exams.
6. To score well in the exam, you should only look up to NCERT Solutions and NCERT Exemplar Class 8 Science Solutions as they are self-sufficient and cover the entire syllabus of CBSE.
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