Friction Questions and Answers:Solved Important Questions Class 11 Physics
Get important questions and answers of Friction for Board exams. View 11th Physics important questions for exam point of view developed by the top IITian faculties from Kota. These important questions and answers will play significant role in clearing concepts of Friction for Class 11and also in revision for Class 12 students. This question bank is designed by keeping NCERT in mind. So learn the concept of friction with these questions and answers and access the notes of various chapters and subjects too.Click Here for Detailed Notes of Friction along with other subjects and chapters.Β
Q. Automobile tires are generally provided with irregular projection over their surface why?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. To increase friction.

Q. Β What does happen to coefficient of friction when weight of body doubled?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. It remains same.

Q. Β  Why synthetic rubber is preferred in tyres making?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. Coefficient of friction between road and synthetic rubber is large.

Q. Is it reasonable to expect the coefficient of friction to exceed unity?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. In case of normal plane surface the coefficient of friction is less than unity, but when the surfaces are so irregular that sharp minute projection and cavities exist on the surface. The coefficient friction may exceed

Q. What is the angle of friction between two surface in contact having coefficient of friction .

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. $\theta=\tan ^{-1}(\mu)=\tan ^{-1}(1 / \sqrt{3})=30^{\circ}$ where $\theta=$ friction angle $\mu=$ coefficient of friction.

Q. Sand is thrown on track covered with snow in hilly area, why?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. Sand is thrown on snow to increase the force of friction, so that tyres of the vehicles may not slip over the snow.

Q. When a wheel is rolling on a road, what is the direction of the frictional force between the wheel and the road?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. As the wheel rolls forward the part of the wheel in contact of the road slides backward hence the force of friction acts in the forward direction along the tangent to the surface of the road and the part of the wheel in contact.

Q. How does lubricant help in minimizing friction?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. The lubricant forms a thin layer between the two surface in contact. Thus sliding friction is replaced by liquid friction which is much smaller.

Q. Why are ball bearings are used to reduce friction

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. Because ball bearing convert sliding friction into rolling friction.

Q. There is a limit beyond which further polishing of surface increase rather than decrease frictional resistance why?

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. Normally friction decreases when smoothness of surface increases however, when surface in contact are made too smooth then binding force of adhesion increase which increases friction. This phenomena is called cold welding.

Q. How do we save petrol by keeping the rubber tyres of our vehicle fully inflated.

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. The weight of the vehicle and its occupants cause some flattening of the part of the wheel in contact with the ground and make some hollow space in the ground hence work is done in lifting the wheel Less work would be done if the rubber wheels are hard that is fully inflated. When they will be flattened less, less work would require less consumption of fuel per unit distance covered.

Q. Friction is a necessary evil, comment.

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. Friction is called a necessary evil. It is necessary because we cannot do without it. At the same time it is an evil because it involves unnecessary wastage of energy. The following facts make the point clear Friction is a necessity

Q. What is the law of friction.

Download eSaral App for Video Lectures, Complete Revision, Study Material and much more...

Sol. There are five laws of friction.(1)The direction of the force of limiting friction is always opposite to the direction in which the motion takes place or tend to take place.(2) The force of friction acts tangentially along the surface of contact of two bodies.(3) The magnitude of the limiting force of friction (F) is directly proportional to the normal reaction (R) between the two surface. i.e. F Β΅ R.(4) Force of limiting friction is independent of the area of the surface of contact of two bodies as long as normal reaction is constant.(5) The force of limiting friction depends on the nature of the surfaces in contact.

eSaral provides you complete edge to prepare for Board and Competitive Exams like JEE, NEET, BITSAT, etc. We have transformed classroom in such a way that a student can study anytime anywhere. With the help of AI we have made the learning Personalized, adaptive and accessible for each and every one. Visit eSaral Website to download or view free study material for JEE & NEET. Prepare these important questions and ace the topic of Friction. Also get to know about the strategies to Crack Exam in limited time period.

• September 29, 2021 at 6:33 am

• September 23, 2021 at 7:05 pm

Good didn’t feel tensed

• September 13, 2021 at 8:17 pm

i need some more questions based on this chapter

• August 2, 2021 at 5:29 am

It is very helpful for me but i want 4 or 5 marks question , numerically and i am not find it anywhere .

• April 14, 2021 at 4:15 pm

hey i asked 5 mark questions verst app i didnt ever seen

• March 25, 2021 at 6:04 pm

Great

• March 17, 2021 at 5:51 pm

this ques.. are more impt.
Iwill be understandπ€π€ this ques.. soln…..
thank you very π€π€π§π§very thak you…π€π€π€π€ππππππ

• March 14, 2021 at 5:07 pm

Tq… For the questions

• March 13, 2021 at 12:03 am

very nice.π€π€π€π€ππππ

• March 13, 2021 at 12:02 am

very nice.π€π€π€π€ππππ

• February 23, 2021 at 4:38 pm

You can visit this link for some interactive quiz on friction https://dewwool.com/a-quiz-on-friction/

• April 2, 2021 at 8:02 pm

Super

• January 30, 2021 at 8:14 pm

Nice! But give few numerical type questions also!

• December 11, 2020 at 12:07 am

nice

• October 27, 2020 at 2:21 pm

Super

• September 30, 2020 at 9:56 am

Very nice

• August 26, 2020 at 1:48 pm

It’s really amazing to clear doubts from her …tysmm

• December 27, 2020 at 11:18 pm

Hi
Give some numerical also.

• August 20, 2020 at 9:02 pm

guys I am in 9 std,,, I wanted few numericals and there are no numericals… I could solve each of the above question… try improve the level and quaity of question…. I am sincerely telling

• October 14, 2020 at 8:32 pm

Tu chup reh

• December 31, 2020 at 4:35 pm

Really of no use

• July 10, 2020 at 8:38 am

Pagol Bhai aro question dibi to