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# Solutions 12. Friction - Text Book Exercise | Class 8 Science - Toppers Study

Topper Study classes prepares ncert solutions on practical base problems and comes out with the best result that helps the students and teachers as well as tutors and so many ecademic coaching classes that they need in practical life. Our ncert solutions for Solutions 12. Friction - Text Book Exercise | Class 8 Science - Toppers Study is the best material for English Medium students cbse board and other state boards students.

## Solutions 12. Friction - Text Book Exercise | Class 8 Science - Toppers Study

CBSE board students who preparing for class 8 ncert solutions maths and Science solved exercise chapter 12. Friction available and this helps in upcoming exams 2023-2024.

### You can Find Science solution Class 8 Chapter 12. Friction

• All Chapter review quick revision notes for chapter 12. Friction Class 8
• NCERT Solutions And Textual questions Answers Class 8 Science
• Extra NCERT Book questions Answers Class 8 Science
• Importatnt key points with additional Assignment and questions bank solved.

Chapter 12 Science class 8

### Text Book Exercise class 8 Science Chapter 12. Friction

• Solutions 12. Friction - Text Book Exercise | Class 8 Science - Toppers Study
• Class 8 Ncert Solutions
• Solution Chapter 12. Friction Class 8
• Solutions Class 8
• Chapter 12. Friction Text Book Exercise Class 8

## Exercise

1. 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.

(a)-relative motion, (b)-nature (c)-heat, (d)-reduces, (e)-less.

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.

(a) Rolling, static, sliding

(b) Rolling, sliding, static

(c) Static, sliding, rolling

(d) Sliding, static, rolling

(c) Static, sliding, rolling.

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

(a) Wet marble floor, dry marble floor, newspaper, towel.

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.

The fractional force will act parallel to the inclined surface, opposite to the sliding of a book.

5. 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?

Soapywater reduce the frictional force applied by the floor to a great extent. That is why, it is difficult to walk on a soapy floor.

6. Explain why sportsmen use shoes with spikes.

Sportsmen use shoes wwiith spikes because spikes produce the desired frictional and thus heelp in holding the ground firmly.

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?

Seema will have to apply a large force because her box is heavier object will have to overcome greater frictional force offered by the surface of contact.

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

Friction is caused by the interlocking in the two surface.

When the object starts slidiing, the contact points on it surface, do not get enough time to lock into the contact points of the other surface. So, the sliding friction is slightly smaller than the static friction.

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

(i) Friction as a friend:

(a) To hold a glass, we have ridges on our palm, which increase the friction between palm and glass.

(b) We do write anything with pen or pencil because there is friction between the surfaces of paper and point of pen or pencil.

(c) Teacher writes on black –board with chalk because of friction between black-board surface and the chalk.

(d) If there is no friction, then a moving body would never stop.

(ii) Friction as a foe:

(a) Friction wears out materials, whether they are screws, ball-bearing or soles of shoes.

(b) Friction can also produce heat, which increases wear and tear of machine parts. It also causes much wastage of energy because this heat is not utilized.

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