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Ever wondered why your shoes grip the ground or why it is hard to push a heavy box(or heavy object)? That is all because of friction. Class 8 Science Chapter 9 Friction question answer helps you understand what friction is, how it works and why it is both helpful and sometimes a problem. The NCERT Solutions for Class 8 Science Chapter 9 are prepared by subject experts based on the latest NCERT syllabus.
These NCERT Solutions for class 8 science Chapter 9 Friction provide clear answers to all exercise questions along with important topics like types of friction, factors affecting it, and methods to reduce or increase it and important formulas. With step-by-step explanations and easy language, these NCERT solutions make problem solving simple and help you prepare better for exams. We have also included the approach to solve the chapter 9 questions so you can understand how to tackle different types of problems confidently.
Below are the solved exercise questions from NCERT Class 8 Chapter 9 Friction. Go through each solution carefully to improve your concept clarity and perform better in exams.
Answer:
(a) Friction opposes the motion between the surfaces in contact with each other.
(b) Friction depends on the nature of surfaces.
(c) Friction produces heat.
(d) Sprinkling of powder on the carrom board reduces friction.
(e) Sliding friction is less than the static friction.
(a) rolling, static, sliding
(b) rolling, sliding, static
(c) static, sliding, rolling
(d) sliding, static, rolling
Answer:
(c) is the correct arrangement.
Static friction > sliding friction > rolling 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
Answer:
The force of friction acting on the car on different surfaces in increasing order will be wet marble floor, dry marble floor, newspaper and towel. Therefore (a) is the correct answer.
Answer:
The frictional force will be opposite to the direction of motion
Answer:
It would make it more difficult for us to walk on the marble floor since the frictional force would further decrease and thus our grip on the floor while walking would become even lesser.
Q6. Explain why sportsmen use shoes with spikes.
Answer:
Sportsmen use shoes with spikes to increase the grip between their feet and the ground by increasing the friction with the help of spikes. This aids them while running on the ground.
Answer:
Seema would have to apply a larger force as she would have to overcome a greater frictional force. The frictional force between two surfaces exists due to the interlocking of the irregularities on the surface. The magnitude of this frictional force depends on how tight this interlocking is which in this case depends on the weight of the boxes which is more in the case of Seema.
Q8. Explain why sliding friction is less than static friction.
Answer:
Sliding friction is less than static friction as the frictional force between two surfaces depends on the interlocking between the irregularities on the surfaces. This interlocking in case of sliding decreases as the contact points does not get enough time to interlock properly thus reducing the frictional force.
Q9. Give examples to show that friction is both a friend and a foe.
Answer:
Friction acting as a friend:
(a) It aids us to walk and cars to move on the roads.
(b)Fire can be ignited using friction.
Friction acting as a foe:
(a) It causes the efficiency of engines to decrease and also damages machinery.
(b) Friction causes the soles of shoes and tires to wear off.
Q10. Explain why objects moving in fluids must have special shapes.
Answer:
When an object is moving through a liquid there is an opposing force offered by the liquid against the motion of the object. To reduce this opposing force objects must have special shapes.
Below are the important topics covered in Class 8 NCERT Science Chapter 9 Friction. These topics explain what friction is, how it affects motion, and ways to increase or reduce it. Go through each section thoroughly to understand the role of friction in everyday life and do well in your exams.
9.1 Force of Friction
9.2 Factors Affecting Friction
9.3 Friction: A Necessary Evil
9.4 Increasing and Reducing Friction
9.5 Wheels Reduce Friction
9.6 Fluid Friction
Below are the simple formulas from Chapter 9, Friction. These will help you understand the nature of friction, its effects, and how it can be managed.
Where:
N= normal force
Where:
To solve questions from Class 8 Science Chapter 9: Friction start by identifying what the question is focusing on whether it is about types of friction , factors affecting friction or methods to increase or reduce it. Carefully read the problem to understand the situation and If the question involves formulas, apply the relevant one like
Frictional force =μ× Normal force,
where μ is the coefficient of friction. Use proper SI units and make sure the values given match the formula requirements.
The chapter-wise NCERT solutions for all the science chapters are listed here along with their links:
Yes, friction, force, motion and pressure are important topics that will be studied in Class 9 NCERT Science Syllabus and also in Class 11 NCERT Physics book
Friction opposes the motion between the surfaces in contact with each other. If there is no frictional force we wont be able to walk.
The following topics are covered in the chapter friction:
9.1 Force of Friction
9.2 Factors Affecting Friction
9.3 Friction: A Necessary Evil
9.4 Increasing and Reducing Friction
9.5 Wheels Reduce Friction
9.6 Fluid Friction
μ represents the coefficient of friction between two surfaces.
The value of the coefficient of friction (μ) varies depending on the materials of the surfaces in contact and other factors such as temperature and pressure. It can range from 0 to 1 or even higher.
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