NCERT Solutions Class 8 Science Chapter 9 Friction

Have you ever wondered why when an object moves across the surface of another object it tends to come to a rest position without any external force acting on it. Have you not watched a ball roll along the ground only to come to a halt after a while? What makes a wet and smooth surface so difficult to walk on? This chapter will give you answers to such questions. NCERT Solutions Class 8 Science - Friction chapter 9, explains friction and examines the reasons for it and its effects on various surfaces.

1.0NCERT Class 8 Science Chapter 9 Friction - PDF Download

Students can access the friction class 8 NCERT pdf questions and answers designed from ALLEN’S best faculties from the table provided below. Friction class 8 NCERT solutions reduce the complex questions and improve the skills of problem-solving to the extent that students are well-prepared for the exams. 

NCERT Solutions offers step-by-step solutions to all the exercises thereby helping the students navigate the topic of friction with ease. Solving friction class 8 extra questions will help students to strengthen their concepts, if they practice these questions regularly and will also boost their confidence.

2.0NCERT Questions With Solutions Class 8 Science Chapter 9 - Detailed Solution

• Fill in the blanks (a) Friction opposes the between the surfaces in contact with each other. (b) Friction depends on the of surfaces. (c) Friction produces . (d) Sprinkling of powder on the carrom board friction. (e) Sliding friction is than the static friction. Solution (a) relative motion (b) nature (c) heat (d) reduces (e) less
• 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: (a) rolling, static, sliding (b) rolling, sliding, static (c) static, sliding, rolling (d) sliding, static, rolling Solution (c) Static, sliding, rolling.
• 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 (1) wet marble floor, dry marble floor, newspaper, towel. (2) newspaper, towel, dry marble floor, wet marble floor. (3) towel, newspaper, dry marble floor, wet marble floor. (4) wet marble floor, dry marble floor, towel, newspaper. Solution (1) wet marble floor, dry marble floor, newspaper, towel
• 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. Solution The book moves downwards. The frictional force is acting opposite to the movement of book. So it acts upwards.
• You spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor. Why? Solution The layer of soap makes floor smooth due to which the friction is reduced and the foot cannot make a proper grip on the floor. Therefore it is difficult to walk on a soapy floor and we start to slip on the floor.
• Explain why sportsmen use shoes with spikes. Solution Sportsmen use shoes with spikes to increase the friction between shoes and surface. The shoes with spikes do not slip while they run or play.
• Eqbal 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? Solution The heavy object will be pressed hard against the opposite surface and produces more friction. So Seema will have to apply a larger force due to more friction.
• Explain why sliding friction is less than static friction. Solution The two sliding objects find less time to get interlocked against each other (objects and irregularities of surface). So they get less friction. Therefore sliding friction is always less than static friction.
• Give examples to show that friction is both a friend and a foe. Solution Examples to show that friction is a friend and a foe: Friction is friend (i) Friction allows us to grip and catch different objects. (ii) It helps us to walk comfortably on the surface. (iii) It helps to minimise the speed or to stop the moving objects. (iv) It helps us to write on paper or blackboard. (v) The things do not move from their places due to friction. Friction is foe (i) Friction causes wear and tear in objects. (ii) It causes damage to the parts of machines. (iii) The machines or tools require regular maintenance due to which a lot of money is wasted. (iv) It reduces the speed of moving objects so more force is required. (v) It does not allow the free movement of objects.
• Explain why objects moving in fluids must have special shapes. Solution The objects moving in fluids must have a special shape. This type of shape is called streamlined shape. The streamlined shape helps to overcome the friction between objects and fluids. The objects have pointed fronts with little broader middle portion which gets tapered at the back.

3.0What Will Students Learn in Chapter 9: Friction?

• The understanding of friction along with the processes which lead to its development in various surfaces.
• The classifications of friction that are present in the world today: stationary, kinetic, and rolling friction.
• The various parameters that influence the extent of friction.
• Friction and its effects in daily life: the positive aspects and the downsides of it also.
•  Ways to either lessen or enhance friction depending on how it is required.
• Examples of friction in practical scenarios engaging human activities including but not limited to walking, writing and driving.
• The nature of friction in fluids and the effects of fluids on motion of objects.