Nature of the fluid.<\/li>\n<\/ol>\nFriction Class 8 Extra Questions Short Answer Type 2<\/h3>\n Question 1. \nGive any two methods each to increase and decrease friction. \nAnswer: \nMethods to increase the friction: \n(a) By making the surfaces rough. \n(b) By removing the lubrication between the two surfaces. \n(c) By changing the rolling friction to sliding friction.<\/p>\n
Methods to decrease the friction: \n(\u0430) By making the surfaces smooth. \n(b) By applying the lubrication between the two surfaces. \n(c) By changing the sliding friction to rolling friction.<\/p>\n
Question 2. \nFollowing are some of the examples which shows that \u2018friction is our friend and foe.\u2019 Choose from the given examples which example is useful for us and which is not. \n(\u0430)\u00a0It allows us to grip and catch any object. \n(b)\u00a0It causes wear and tear in objects.<\/p>\n
Helps in writing. \nIt helps to minimise the speed or to stop any moving objects. \nAnswer: \n(a) Useful, \n(b) Not useful, \n(c) Useful, \n(d) Useful.<\/p>\n
Question 3. \nWhat do you mean by lubricants? What is their use? \nAnswer: \nThe substances which reduce friction are called lubricants. To increase efficiency, friction has to be reduced. This can be done by applying oil, grease or graphite in between the moving parts of a machine. Then its thin layer is formed there and moving surfaces do not directly rub against each other. In this way, interlocking of irregularities is avoided to a great extent and movement becomes smooth.<\/p>\n
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Question 4. \nSite some examples when we prefer to reduce friction. \nAnswer: \nSome examples where we prefer to reduce friction are: \nItem used Used on Used for \n(i) Fine powder \nCarrom board \nFor easy movement of sticker.<\/p>\n
(ii) Lubricants and air cushion \nMoving machine parts<\/p>\n
Reduce heat production and hence increasing efficiency. Also decreasing wear-tear rate. \n(iii) Ball bearings Machine moving parts \nTo convert sliding friction to rolling friction.<\/p>\n
Friction Class 8 Extra Questions Long Answer Type<\/h3>\n Question 1. \nWhat are the different types of friction? Arrange them in the increasing order of their magnitude. \nAnswer: \nStatic friction: The friction which acts between the two surfaces in contact when there is not actual relative motion between the two surfaces. It is necessary for walking also because without this static friction, feet would slip out, making it difficult to walk.<\/p>\n
Sliding friction: The friction which acts between the two surfaces in contact when there is actual relative motion between the two surfaces. When we push a trunk and the trunk moves, the friction acting in this case is sliding friction.Therfe is sliding friction between the brake pads and bike rims each time we use bike\u2019s brakes. This friction slows the rolling wheels.<\/p>\n
Rolling friction: The friction which acts between the two surfaces in contact when one surface rolls over the other surface. The friction in the ball bearings is rolling friction. Rolling friction is much weaker than sliding friction or static friction. This explains why most forms of ground transportation use wheels, including bicycles, cars, 4-wheelers, roller skates and scooters.<\/p>\n
Hope the knowledge provided regarding the Friction Class 8 Extra Questions and Answers has helped you to the possible extent. For more info feel free to reach us and we will guide you at the earliest possibility. Stay connected to our site to avail latest updates on Extra Questions for Various Classes instantly.<\/p>\n","protected":false},"excerpt":{"rendered":"
Friction Class 8 Extra Questions and Answers Science Chapter 12 PDF are solved by experts and will guide students in the right direction. Students can get how to tackle different questions easily by solving the Extra Questions for Class 8 Science Question bank on a regular basis. Class 8 Science Chapter 12 Extra Questions and …<\/p>\n
Friction Class 8 Extra Questions and Answers Science Chapter 12<\/span> Read More »<\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","spay_email":""},"categories":[7],"tags":[],"yoast_head":"\nFriction Class 8 Extra Questions and Answers Science Chapter 12 - MCQ Questions<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n