The appropriate weight to be used with each spring depends on the stiffness of spring, you will have to use your judgment to decide how much weight to use with each spring. State one way in which the friction between the wheel and its axle can be reduced. Spring provides many approaches for doing the same thing, and we can even mix the approaches and use both JavaConfig- and Annotation-based configuration styles in the same application. Answer: Name any two machines in which ball bearings are used. But we can fall if friction (denoted by “f”) is not present as the large ground can apply a large force . A. Answer: Question 26. Answer: Answer: What is the special name of frictional force exerted by fluids (like air or water)? Kabaddi players rub their hands with dry soil before playing so as to increase friction. Spring Balance This type of balance utilizes Hooke's Law which states that the stress in the spring is proportional to the strain. This is because, the heel of the shoe is interacted with the ground more than the other part and due to friction, the treads of the shoe sole wear out. Question 66 B. If we oil between the two surfaces, say part1 and part 2 of a machine, then the oil layer will allow less contact of the two surfaces with each other as you can see in the figure below: B. Thus, there is no friction. Weighing scale for a baby includes a ruler for height measurement. Let's see a simple example, where we are having main() method in another class. Wet marble floor, Dry marble floor, Newspaper, Towel What is not so obvious is that the spring balance doesn’t measure force directly, instead it changes length as a result of force being applied to it. Question 21. An aeroplane moving in the sky. B. drab C. 5 N See more. Explain why: You will learn the principles of Pilates including breathing, control, precision, centering, flow, and concentration. FET-based output stages are questionable in this size due to stability considerations and the need for extra-large heatsinking, so the CA-200 uses stable, efficient bipolar transistors. We can have multiple classes in different Java files or single Java file. Answer: The spring + mass system can stay at the equilibrium point indefinitely as long as no additional external forces come to be exerted on it. Why? B. Answer: The static friction > Sliding Friction > Rolling friction Thus the rolling friction will be less than 20N. Question 11. Answer: D. 50 N Pilates creates a balance of energy in your mind and your body by requiring you to use both throughout your practice. What enables us to fix nails in a wall and knots to be tied? A) Mass of an object Heavy machines can be moved from one place to another with the help of wheels because wheels can be rolled and the amount of force is also comparatively less. When we pull the upper wooden block A over the lower wooden block B by applying a force, then the irregularities of their rough surface get entangled or locked with one another. 45N The Spring Tool Suite is an open-source, Eclipse-based IDE distribution that provides a superset of the Java EE distribution of Eclipse. C. a layer of grease Answer: Answer: (c) Friction produces heat C. 55N The air drag obstructs the vehicle to move forward and the fuel is consumed mainly for opposing this opposite frictional force. Archimedes principle is used in making (a)aeroplanes (b)fast moving trains (c) space ship (d) submarines 13. 2. The frictional force exerted by a fluid is called: Java supports javax.annotation.Resource annotation using JSR-250 that is applied on component class and fields or methods of component class. Why do tyres of cars wear out gradually ? Question 9. Rolling friction is the friction or drag which opposes the motion when a body rolls. (k) The shape of an aeroplane is similar to that of a bird in flight. Question 19. Question 12. I have the following setup . Question 13. This video is unavailable. Answer: To see a demo of the currently recommended client-side-load-balancing approach, please check this guide. Frictional force is responsible the wearing of car tyres. Assignment no. Question 90. Answer: The friction is produced due to the contact of the two surfaces of the table and the book. True 6. The @Bean annotation tells Spring that a method annotated with @Bean will return an object that should be registered as a bean in the Spring application context. Reply. When the body is in stationary state or is at rest, the frictional forces acting on the body is known as static frictional forces. A. Question 84. When we apply force, F on a book, the book slide (Fig A). To move one object over the other ,we have to apply a force to overcome interlocking of the irregularities in their surfaces. The Professor says: February 6, 2016 at 12:08 pm. Question 48. Here you can read Chapter 12 of Class 8 Science NCERT Book. Friction can be reduced by using ball bearings in some machines. B. rubbing of sand paper on glass table top What is drag? D. static friction is greater than sliding friction (a) which one is the smallest? Question 15. Suppose, a person is pushing a heavy box, then he is applying say force F1. Why does oiling the axles of a bicycle make the bicycle move more easily? B. sliding friction is less than force of gravity Answer: Larger the stretching of street spring ,greater will be the magnitude of force applied. Question 66 A. Seema will have to apply larger force than Iqbal. Question 35. Scroll down for Friction from NCERT Book Class 8 Science Book & important study material. This gives Hooke’s law for this Newton spring balance as “applied spring force” equals 0.1 times the “spring extension”. The objects moving in fluids have streamlined shape so as to reduce the air drag or fluid friction that opposes their motion in any fluid. Topics covered are friction, causes of friction, factors affecting friction, methods to reduce friction, advantages and disadvantages of friction, fluids and fluid drag. About Spring Tool Suite IDE. Answer: Question 38. Whenever we push a very heavy box kept on the ground, it does not move at all because frictional force balances the force that we apply. A body shape which offers very little resistance to the flow of a fluid around it, is called streamlined shape. Explain why, objects moving in fluids should have streamlined shape. D. 65N Question 6. Answer: D. tread True 15. The book starts sliding down slowly sliding slowly, because the sliding friction is less than force of gravity. Question 74. Explain with the help of diagrams, how the use of oil reduces friction between two surfaces in contact with each other. Answer: D. streamlined shape (k) The shape of an aeroplane is similar to that of a…………in flight. A and B GCC’s anatomy and physiology (A&P) courses explore the human body. C. 4.8 m A spring balance can measure both the force acting on it as well as the weight of the object. Question 33. Answer: What prevents you from slipping every time you take a step forward? Question 93. v) ----- can be used to reduce friction. Question 53. Due to ice, the friction reduces and the car spins. Literature review on the use of spring balance in teaching the concept of weight. Timbren Aeons will provide a long lasting and heavy hauling suspension enhancement that can even benefit Class 8 trucks. Let's see a simple example, where we are having main() method in another class. The paper surface offers more friction to the pencil when we write on the paper, in this way when the pencil is rubbed on the paper, some bits of graphite come on the paper and we are able to write. The USP clearly defines when Class 1, Class 2 and Class 3 weights should be used. And although it's useful, there are use cases for which this annotation alone isn't enough for Spring to understand which bean to inject. (b) which one is the largest? Answer: Answer: Question 25. The static friction > Sliding Friction > Rolling friction. Stretching of the spring is measured by a pointer moving on a graduated scale. A person has applied some mustard oil on his hands. Out of sliding friction, static friction and rolling friction: The weight of an object can be measured by a: It decreases the friction of a surface. NCERT Solutions for Class 8 Science Chapter 12 Friction Topics and Sub Topics in Class 8 Science Chapter 12 Friction: Section Name Topic Name 12 Friction 12.1 Force of Friction 12.2 Factors affecting Friction 12.3 Friction : A Necessary Evil 12.4 Increasing and Reducing Friction 12.5 Wheels Reduce Friction 12.6 Fluid Friction Friction Class 8 Science […] C. Towel, Newspaper, Dry marble floor, Wet marble floor The class-level annotation maps a specific request path or pattern onto a controller. This relationship is usually linear; i.e., if the load is doubled, the deformation is doubled. Answer: As the roughness of the surface increases, the friction force increases. (d) Friction prevents our foot from slipping over the ground A. sliding friction is greater than static friction Example- Air and Blood. @SpringBootApplication Annotation @SpringBootApplication annotation is a convenience annotation introduced from Spring Boot 1.2.0.If you have worked on the earlier spring boot versions, it is common that main class always annotate with the following annotations: @Configuration: This annotation is not specific to the spring boot applications. A spring scale or spring balance or newton meter is a type of mechanical force gauge or weighing scale.It consists of a spring fixed at one end with a hook to attach an object at the other. Good work. It must be remembered that action and reaction always act on different objects. 5.2.12.RELEASE GA: Reference Doc. Also, practise the laws of liquid pressure and learn to apply it … Question 46. Mud offers more friction than glass and we are able to from a grip on the earthen plot. Using talcum powder to reduce the friction on carom board. A beam balance (or beam scale) is a device to measure weight or mass.These are also known as mass scales, weight scales, mass balances, weight balances, or simply scales, balances, or balance scales.. (a) least friction, and The sliding friction is less than static friction because, in sliding friction, the interlinking of the two surfaces is for very short time. Use this to examine the effect of the following on the balance of payments in the fixed exchange rate system and exchange rate in the flexible exchange rate system: in a one-country model (10 points) a. D. wooden cup Choose the correct option. Why are cars, aeroplanes and rockets streamlined ? The friction between two surfaces does not depend on one of the following. Frictional forces helps things to move and stop. Question 8. You can configure some bits of a Ribbon client by using external properties in .ribbon. Friction do not produce heat. Rolling friction comes into play when a book kept on cylindrical pencils is moved by pushing. Answer: 1. In both cases, the relationship between the magnitude of force F used to stretch or compress the spring by a length Δ x is given by Hooke's law as follows: | F | = k | $\Delta x $ | where k is the spring constant. But, on rough surfaces, the irregularities are very large. Answer: Question 54. These materials are available at a hardware store. A. north direction D. Sliding, Static, Rolling Gymnasts apply a coarse substance to their hands to increase the frictional forces on their hands so that they can hold firmly. The well-polished floor offers very less resistance. Round Robin – Requests are distributed across the group of servers sequentially. Question 10. Thus, the object is able to move easily due to less friction. API Doc. B. steamlined shape B. sliding friction is less than force of gravity By applying any lubricant , say grease, one can reduce friction between those machine parts which rub against each other to avoid wear and tear. 5. Then acts a force of friction, f (Fig B) D. bus Friction is caused by the interlocking of irregularities in the surface of two objects which are in contact with each other. (b) Climbing a greasy pole is very difficult because the greasy pole offers very less friction to the feet of the person climbing on it. If the static friction between two surfaces P and Q is measured to be 50 N, then the sliding friction between these two surfaces is most likely to be : Answer: Question 65. SumoSprings have a wide variety of applications and are a good choice when a balance of weight support and comfort are desired. Question 82. B. a dry lubricant Digital NCERT Books Class 8 Science pdf are always handy to use when you do not have access to physical copy. Frictional force is responsible the wearing of footsteps of over-bridges. Question 94. Explain how, friction enables us to walk without slipping. To do so, use the enum reference variable in the switch and enum constants or instances in case statements.. 1. Question 95. Why is it difficult to light a matchstick by striking it on a smooth surface ? The class attribute is often used to point to a class name in a style sheet. (b) Sliding friction is …………..than the static friction. D. static friction is greater than sliding friction Question 20. We can have multiple classes in different Java files or single Java … Question 80. Spring Cloud Netflix Ribbon is now deprecated. A. trimlined shape Answer: Question 75. A spring balance measures force. (g) The friction when something moves through a liquid or gas is called drag. Which of the following statements is incorrect ? Rolling, Sliding, Static Answer: Question 16. A spring balance can be used to measure A car is moving towards North. Question 88. Fluids are those whose which do not have any shape and flow like liquids. Question 7. The force that opposes the motion of an object is called friction. D. only D Answer: Question 4. Name one example from everyday life where wheels (or rollers) are used to reduce friction. So, there is no net movement of this box. By studying the Newton spring balance we may appreciate the way in which the law works and how to use it to measure force. False 10. Du to which, the person slips down again and again. Reply. Annotating a class with the @Configuration indicates that the class can be used by the Spring IoC container as a source of bean definitions. Why does a fast car slow down if its engine is switched off? Dynamometer is used to measure the forces acting on any object. Question 27. So to allow proper functioning, they have to be replaced. Answer: B. If the surface is smooth, then the surfaces in contact have very less interlockings and the thus the friction is less. If the sliding friction between two surfaces is found to be 8 N, then the static friction between these two surfaces is most likely to be: D. 5.2 m Balance definition is - physical equilibrium. (a) when a block of wood kept on table moves slowly ? API Doc. (e) Sprinkling of powder on the carom board reduces friction. Which type of surfaces produce B. static friction into sliding friction Some of the particles on the surface of objects are in the form of tiny hills while other form grooves.The tiny hills or grooves on the surface of object are called. Answer: If the static friction between two surfaces X and Y is found to be 20 N, then the rolling friction between these two surfaces should most likely be : Also after the chapter you can get links to Class 8 Science Notes, NCERT Solutions, Important Question, Practice Papers, etc. The static friction > Sliding Friction > Rolling friction. Why does this happen ? Answer: Question 69 A. (f) Ball bearings reduce friction because they roll rather than ‘slide. The spring balance measures weight of an object. For example, anatomy labs might examine the organization of the heart through dissection, models, and tissue slides. When you touch an object, you apply a force on the object, whether that object is the key of a computer keyboard, a door handle, a bed or any of the hundreds of items you interact with each day. (b) Sliding friction is less than the static friction. The traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum. I am very impressed and I request you to make such class notes of science from ncrt of class 8 th, Your email address will not be published. Question 70 A. B. weight of the object which tends to move on the surface of other object What makes the steps of foot over-bridges at Railway Stations to wear out slowly ? ii) Friction is caused by the ----- on the two surfaces in contact. API Doc. Give an example to show that friction depends on the force with which the two surfaces are pressed together. D. west direction The mass of solid is (a) 112.5 g (b) 118 g (c) 120 g (d) 125 g. Question 22: A boy added few cubes of ice to a glass tumbler containing 20 ml of water. These class files are used to write business logic in a different layer, separated from @RestController class file. Question 18. C. degree of smoothness of surfaces of two objects in contact with each other Answer: A spring balance is used to measure the weights of object with the help of tension force. Castor oil and Grease are the two common lubricants. (d) Friction prevents our foot from…………..over the ground. What is the name of ‘special shape’ which is given to objects moving through air (or water) to reduce drag? C) Density of an object Question 69 B. Larger the stretching of street spring ,greater will be the magnitude of force applied. Answer: To implement this state, we use an array instead of a couple of variables, because all external variables used inside the lambda have to be effectively final. Least Connections – A new request is sent to the server with the fewest current connections to clients. Question 60. Where does this force act? Question 24. A horse can’t pull a cart without friction. A. rolling friction into sliding friction A rough surface will cause more friction than a smooth surface. False 3. Question 42. What is magnitude in Physics, is certainly a question of immense importance in science. (c) when a block of wood kept on cylindrical iron rods moves? 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