In this paper we describe a simple alternative to the telephone book friction experiment, a classic demonstration where a small force generated for example by. The definition of a vector, some physical examples, and vector addition and subtraction. Intuition on static and kinetic friction comparisons. The aim of our experiment is to illustrate the friction force in a. Youve heard that word, heck, maybe youve even used it. The resistance to movement that occurs when two objects are in contact. Friction definition of friction by the free dictionary. Take two phone books and lie them face up, with the spines facing away from each other. Take the above myth busters clip for example, when the friction in between the sheets of a phone book in between the pages of a second phone book make them extremely difficult to separate. The definition of friction, as listed in websters is a force that resists the relative motion or tendency to such motion of two bodies in contact, in lehmans terms, friction is what makes things hard to move. An automobile uses onequarter of its energy on limiting the friction.
Learn more about how mastering physics helps students succeed. Friction friction is a force that opposes relative motion between systems in contact. Are two interlaced phone books impossible to pull apart by any means. Friction, force that resists the sliding or rolling of one solid object over another.
When the force of friction covers a big area, it becomes very strong. Of course, friction only occurs when two surfaces are. Friction forces gcse physics single science revision. Scientists figure out why interleaved phone books cant be pulled apart. In general, the smoother an object, the less friction it will create. Introduction to science and the realm of physics, physical quantities, and units. Table 1 shows the static friction coefficients for some common materials. Material losing electron is positively charged and material gaining electron is negatively charged. It is the cause of many problems, but we couldnt get along without it. Weve all heard about it and blame it for all sorts of things. Physics is the most fundamental branch of physical science which deals with the study of matter and energy, and their relationship with each other. This lesson shows an example with discussion of the general principles. Static friction is when the friction is strong enough to stop movement between two objects.
Phone book paper is on the rougher side, probably 0. Key topic areas are mechanicsbased treatments of friction, including typical problems and equations. Friction and gravity exist in every aspect of a persons life. Friction is a type of force, or a push or a pull, that can act on objects. Its direction is opposite the relative velocity or intended velocity. Why it takes tanks to separate two phone books the pipettepen. Friction accounts for how your feet move across grass, for example, compared to how an ice skate moves across ice. Types of charging charging means gaining or losing electron.
Explore the physics of friction using sticky notes. A higher normal force will result in higher friction. Physicists solve the mystery of interleaved phone books. Friction is due to a normal force, meaning that the direction in which. Friction is the force that resists motion when the surface of one object comes in contact with the surface of another. Definition friction is a catchall word that refers to any force that resists relative tangential motion or intended motion. Each page in contact has the friction caused by the weight of the pages above it pushing down. A simple alternative to the phone book friction demonstration.
Find out jamies idea of a great name for a baby, as well as his preferred title for a romance novel should he write one. The energy lost to friction is turned into sound and heat. Friction definition and meaning collins english dictionary. In this paper we describe a simple alternative to the telephone book friction experiment, a classic demonstration where a small force generated. Friction can be reduced by using a lubricant such as oil or silicone. In this context normal means perpendicular to the surface. Low friction surfaces are in increasingly high demand for hightech components such as computer storage systems, miniature motors, and aerospace devices. We recognize that relationship when we divide friction force by normal force and identifying the quotient as the coefficient of friction. The more pages you put together, the bigger the area and the more friction you create. Key to the phenomenon of spectacular friction forces between two interleaved phone books is a simple geometrical conversion of the traction force to an orthogonal component which. Phone book friction blog alphageek aplusphysics community. Coefficients of static friction for a few common materials.
The pages of the sticky note pads are held together by friction. While the myth was busted, the mythbusters pointed out that it took 8,000 pounds of force to pull the phone books apart, meaning that you could. When you throw a ball up, gravity causes the ball to fall down. In short, it is extremely difficult to pull apart two phone books whose.
Friction description definition a force that opposes motion when a force is applied to a body resting on a rough plane so that the body moves or tends to move, a frictional force acts on. Matters can be charged with three ways, charging by friction, charging by contact and charging by induction. Without getting too technical, friction is simply a force that reduces the motion between objects that are in contact with each other. Relative tangential motion is a fancy way to say slipping or sliding. The force in question is the friction between individual sheets amplified by the. Adhesion varies with substances in contact and is a complicated aspect of surface physics. Even a small number of interleaved pages can result in a surprisingly large amount of friction, making the sticky notes impossible to pull apart. Weidner, physics today both a historical treatment and a critical analysis, this work by a noted physicist takes a fascinating look at one of the fundamental and primordial notions in physical theory, the concept of. Correction to force of friction keeping the block stationary. Friction simple english wikipedia, the free encyclopedia. Scientists figure out why interleaved phone books cant be. The study of sliding friction is one of the oldest problems in physics, and certainly one of the most important from a practical point of view. Shuffle two phone books together like a deck of cards.
If we push a book on a horizontal table with a certain initial velocity, it eventually comes to rest. When tempers flare during a particularly complicated myth, jamie offers up a simple solution. Its well known that two phone books with their pages. This phenomenon is commonly demonstrated with phone books. The fact that the pages of two phone books are interleaved means that friction as well as weight is preventing them from being separated. The average normal force between pages then is 12w book. Can a shark be blown up like they did in deep blue sea. A person sliding a book across a table creates friction. About 20 percent of the engine power of automobiles is consumed in overcoming frictional forces in the. In physics the frictional force between two surfaces is determined by something called the coefficient of friction. To read concepts of force is to gain a new and profound understanding of force and dynamics.
Friction is a force that acts to stop the movement of two touching things. Physicists solve the mystery of interleaved phone books mit. In this paper we describe a simple alternative to the telephone book friction experiment, a classic demonstration where a small force generated for example by the bending of the outer pages is amplified by the large number of surfaces in contact, resulting in a huge maximum static friction force that has to be counterbalanced in order to separate the books. It is impossible to separate two interlocked phone books due to the massive amount of friction between the 800 pages of each book. There is less friction between smooth surfaces than between rough surfaces. The mythbusters tried to pull the two phone books apart with human power, which was unsuccessful. Part of the friction is due to adhesive forces between the surface molecules of the two objects, which explain the dependence of friction on the nature of the substances.
Mastering physics is the teaching and learning platform that empowers you to reach every student. For example, almost every movement you make, such as walking and running, involves friction. A pair of cars also failed at pulling the phone books. Charging by friction when you rub one material to another, they are charged by friction. This shows that there is some force opposing the motion of the book. There is also an interaction pair of friction forces. It is friction, for example, that slows down a ball rolling on grass and causes the blade of a saw cutting wood to get hot. Knots are another example, looping a rope around itself greatly increases the friction. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The rougher the surface of an object is, the more friction will be produced.
The mechanical advantage of a machine is reduced by friction, or in other words, the ratio of output to input is reduced because of friction. For example, page one of the first phone book should overlap page one of the. The aim of our experiment is to illustrate the friction force in a dramatic way and to simplify the tedious job of interleaving a large number of book. Isaac physics a project designed to offer support and activities in physics problem solving to teachers and students from gcse level through to university. People have tried pulling two interleaved phone books apart by playing tug. Try pulling apart two interleaved phone books and youll inevitably be defeated by huge frictional forces. Then interleave the pages and try to pull the books apart. Pulling apart two interleaved phone books stack exchange. Frictional forces, such as the traction needed to walk without slipping, may be beneficial, but they also present a great measure of opposition to motion. What is friction the ohio state university at lima. One of the simpler characteristics of friction is that it is parallel to the contact surface between systems and always in a direction that opposes motion or attempted motion of the systems relative to each other. In relation to this interleaved phone book the normal force is applied to all the pages in series instead of in parallel.
When combined with educational content written by respected scholars across the curriculum, mastering physics helps deliver the learning outcomes that students and instructors aspire to. Will tory and kari successfully pull apart two phone books in 30 minutes without breaking their teeth. Of course, friction only occurs when two surfaces are pushed together, and. If there are 999 pages in total in contact with each other, the friction between the pages is equal to 500 times the friction between one book and a table. Simple physics definition is, physics is basically the study of how objects behave.
The friction between two objects determines how difficult it will be to slide one object across another. In this diagram, the book is moving to the right across the table. The force in question is the friction between individual sheets amplified by the huge number of pages in each directory. It is now known that friction resists motion, does this mean that friction is bad. Mythbusters phone book friction full episode video. As a result, this book does a fi ne job of comprehensively covering the subject. Believe it or not, this commonly viewed as weak force can add up. If there is friction between people, there is disagreement and argument between them. It was guillaume amontons who first established that there existed a proportional relationship between friction force and the mutual pressure or force between the bodies in contact. Why cant two interleaved phone books be pulled apart. Get 50% off quizlet plus through monday learn more. For two books of pages each there are 1999 pagesurfaces in contact. In the case of friction at single interface then its true that increasing the surface area doesnt generally help much, as force is spread over a larger area in parallel and, as a previous poster said, the reduction in pressure counteracts the increase in area.