Phone book friction physics problems

The coefficient of kinetic friction between the box and the surface of the incline is 0. There are sliding friction experiments, a phone book friction experiment, a way to make rice stick together, an experiment to create frictional heat, and lots more friction experiments for all ages. For example, rubbersoled shoes slip less than those with leather soles. Friction problems for the following problems, calculate the force of friction acting on the object. The intent is to stimulate awareness and understanding of the physical world for people who are interested in physics. This page demonstrates the process with 20 sample problems and accompanying. A box is sliding up an incline that makes an angle of 20 degrees with respect to the horizontal. Find the tension in the rope the force the rope is applying. Maybe you want to know how the physics you were taught in school applies to the real world. Friction on inclined surfaces in physics problems dummies.

Practice finding the acceleration of an object when static and kinetic friction forces are included. Pro problems physics motion and forces linear motion force friction static friction book against wall i am pushing a book mass. It is the cause of many problems, but we couldnt get along without it. Learn the physics behind the surprisingly powerful force of friction. The maximum allowable friction force at the wall is. Below are a series of activities problems that you can use to check your understanding of many of the topics and skills you will need to be familiar with for the ap physics 1 test. Kinematic equations relate the variables of motion to one another. The convenient thing to do for this problem is to let friction be the negative one. Forces in physics, tutorials and problems with solutions. Forces in physics, tutorials and problems with solutions free tutorials on forces with questions and problems with detailed solutions and examples. In fact, if the experiment is done at a larger scale using two phone books, those phone books can even be attached to a crane to lift the weight of an entire car.

The book can be very useful to physicists, chemists, materials scientists and engineer who want to understand the basic aspects of sliding friction. Put friction to the test with this fun family physics activity. When the force of friction covers a big area, it becomes very strong. For example, if youre unloading a refrigerator from a. A book of mass 1kg is held to a vertical wall by a persons hand applying a 20n force directly toward the wall. If maximum friction force is less than friction force required for equilibrium, block will slide. The thickness of the doubledup phone books where the pages interleave is twice as thick as the individual phone books at the binding. Scientists figure out why interleaved phone books cant be. The fact that the pages of two phone books are interleaved means that friction as well as weight is preventing them from being separated. Friction points up because the block slides down, and friction always points.

Tension results in a compression at the middle that results in a goodsized normal force, and hence a goodsized static friction force. Now that we have the basics down, lets move on to more complicated forces. For each problem, on a separate sheet of paper draw a picture of the situation, the free body diagrams necessary, and solve the problem. If values of three variables are known, then the others can be calculated using the equations. Combine equations 1 5 to obtain an equation for note that the length of the ladder l cancels out. As with most every force problem, start by drawing a freebody diagram. Where fn is the normal force, fg is the force of gravity fg mag mg on earths surface, and ff is the force of friction. If youre seeing this message, it means were having trouble loading external resources on our website. Friction is a force that is around us all the time that opposes relative motion between surfaces in contact but also allows us to move which you have discovered if you have ever tried to walk on ice. Two equalsize books does not have to be a phone book or two thick magazines, notepads or tablets. Physics 1 forces and newtons laws of motion friction. Try pulling apart two interleaved phone books and youll inevitably be defeated by huge frictional forces.

Just calculate the force per page from the formula f coefficient of friction x normal force and then multiply this times the number of pages. Phone book friction science activity at science buddies phone book friction science activity at scientific american making connections. Its well known that two phone books with their pages interleaved are almost. If you wet the books, the paper material is weaker, and the friction force is probably enhanced, so its easier to break the books binding. Part of the friction is due to adhesive forces between the surface molecules of the two objects, which explains the dependence of friction on the nature of the substances. Assume that the block starts from rest at the bottom of the hill, and neglect friction.

Isaac physics a project designed to offer support and activities in physics problem solving to teachers and students from gcse level through to university. 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. The phone books wouldnt come apart using all the mythbusters gadgets and even attaching the phone books between two cars. Friction acts at the contact of two surfaces and acts to resist the relative motion of these two surfaces. Teach with fergys physics problems video walkthroughs. Will tory and kari successfully pull apart two phone books in 30 minutes without breaking their teeth. How many pages have to be interleaved before the books resist being pulled apart. We have to rely heavily on observations for whatever understandings we can gain. Youve heard that word, heck, maybe youve even used it. The friction between two objects determines how difficult it will be to slide one object across another. The coefficient of friction between card and road is 0. The rope is parallel to the incline and has a tension of 100 n. Low friction surfaces are in increasingly high demand for hightech components such as computer storage systems, miniature motors, and aerospace devices.

Intuition on static and kinetic friction comparisons. 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. Determine whether the block is in equilibrium and find the value of the friction force. Adhesion varies with substances in contact and is a complicated aspect of surface physics. Friction acts tangentially along surfaces in contact, in the direction that opposes motion. Are two interlaced phone books impossible to pull apart by any means. Physicists solve the mystery of interleaved phone books. This website contains a variety of physics problems, complete with solutions, taken from real world applications. If we push a book on a horizontal table with a certain initial velocity, it eventually comes to rest. With the book held at rest, what the is frictional force keeping the book from sliding down the wall. Why wear a piece of apparatus with a large surface area if surface area doesnt affect friction. When one vector is opposite another, one of the two needs to be negative.

Friction accounts for how your feet move across grass, for example, compared to how an ice skate moves across ice. While a common force, the behavior of friction is actually very complicated and is still not completely understood. A popular science demonstration shows that when you overlap the pages of two phone books, they are nearly impossible to pull apart. This net force will cause an acceleration opposite the direction of motion. The variables include acceleration a, time t, displacement d, final velocity vf, and initial velocity vi.

This comprehensive and wellwritten book is entirely devoted to fundamental aspects of friction, and especially to new theoretical and technological problems of sliding friction. The surface of the inclined plane is assumed to be frictionless. Since most people do not have two phone books sitting around, we will show you how you can do the same experiment with sticky notes. In essence, the applied force is a mechanical force being applied to an object by another object. Why cant two interleaved phone books be pulled apart. Take two phone books, each about 1 kg about pages and carefully shuffle the pages together, each page of one phone book alternating with a page of the other phone book. Applied force the applied force is special, in that it is a generalized and simplified form of many different forces.

Explore the physics of friction using sticky notes. Phone book friction, from mythbusters the enigma of the two interleaved phonebooks pdf, from cornell university library slippery science. The maximum allowable friction force at the ground is. In this phone book case however the area is increased by interleaving many friction surfaces so that the force is applied in series to all the surfaces without the corresponding decrease in pressure. The humble phone book has been the subject of one of the more entertaining physics puzzles in recent years. The friction force is so strong that the margins are torn apart even when the books are dry. This shows that there is some force opposing the motion of the book. How fast is the block going after moving 40 m up the hill.