Experiment to Determine the Coefficient of Friction

Experiment to Determine the Coefficient of Friction Student Name: Ahmad Raza Summary: This experiment has two aims. The first aim of this experiment is to determine the coefficient of friction on an inclined plane by using various materials tray. Secondly, to verify that the force have already found which were required to move a body on an inclined plane. We have provided apparatus to do this experiment that include stainless steel plane, load hanger, different weights and 4 trays of different materials such as aluminium, brass, nylon and ferado. Firstly, we place tray at the middle of plane and apply weight on weight hanger until tray starts to move. Note the angle and find the coefficient of friction. For this purpose we have found the Normal force and sliding. Then, by using formula of coefficient of friction we found the value, which was approximately 0.18 at 10Â °, 20Â ° and 30Â °. Nevertheless, the additional 10N weight was added but the friction coefficient but the angle will remain same. The experiment was taken by under good circumstances. However, errors can be reduce by overlapping the mistake that was take place in this experiment. This experiment could be done exactly the same as international standard if the following conditions apply on it. CHAPTER 1 INTRODUCTION AIMS AND OBJECTIVE The aims of the friction experiment are to find the coefficient of different combination of material which is in this experiment, the steel bar. Making use of inclined plane, also to study equilibrium and non-equilibrium of a body of an incline plane under the action of the force. The objective is to understand that a coefficient of friction could be determine via incline plane, collect experiment data and calculate the corresponding results and coefficient and finally to compare the value of coefficient generated from different pairs of surface. 1.2: THEORY AND BACKGROUND: Friction can be defined as the force that will resists the relative motion of solid surfaces which are sliding against each other. There are mainly three types of friction. Dry friction, Fluid friction and internal friction but this particular experiment was just examined only for dry friction. Dry friction is the encountered when two dry surfaces are in convention if there is a tendency of sliding. However this dry friction has split into two sub frictions as static and kinetic. Commonly, kinetic frictional force will be less than the absolute maximum value from the static frictional force. This static frictional force is derived as fs = ÃŽ ¼sN, while kinetic frictional force is fk =ÃŽ ¼kN, where ÃŽ ¼s is the coefficient of static friction, ÃŽ ¼k is the coefficient of kinetic friction, N is the normal force and ÃŽ ¼ is the proportionality constant and called coefficient of friction. An inclined plane can be defined as any plane surface positioned at an angle with respect to the horizontal plane. At the moment of sliding, the friction force must be the same to the element of weight acting down the plane. ÃŽ ¼W .cosÃŽ ¸ =W .sinÃŽ ¸ This leads to the concept of the angle of the friction ÃŽ ¼ = tanÃŽ ¸ CHAPTER 2 APPRATUS AND experimental procedure 2.1: APPRATUS: Adjustable stainless steel plane complete with base .5N load hanger Weights Trays of Aluminium, Brass, Nylon and Ferado Fig1.1: Wood plane and trays 2.2: experimental procedure: As we discussed above, we have two aims for this experiment. Each aim has different procedure. 2.2.1: Following procedure is to find the angle of friction on a steel plane by using different materials. We have given four trays for this experiment such as Aluminium, Brass, Nylon and Ferado. First of all set the plane of stainless steel at 0 slope by ensuring that it is in horizontal plane. Afterward, set the tray of any material at the middle of stainless steel plane then apply weight at the end of plane by weight hanger and note the angle of inclination when tray starts to slide. Take coefficient of Tan ÃŽ ¸ to evaluate static deflection (ÃŽ ¼s).Repeat the same procedure three times and take the average. Subsequently, to evaluate the angle of sliding friction (ÃŽ ¼k) , place the tray again in the middle of plane and reduce the tilt as this time tilt was increased, we keep pushing the tray till it started to move and note the angle for three times and take the average. Static deflection (ÃŽ ¼s) Measure angle ÃŽ ¸ for static deflection by using Aluminium tray Table 1.1: Aluminium tray Measure angle ÃŽ ¸ for static deflection by using Brass tray Table 1.2: Brass tray Measure angle ÃŽ ¸ for static deflection by using Nylon tray Table 1.3: Nylon tray Measure angle ÃŽ ¸ for static deflection by using Ferado tray Table 1.4: Ferado tray Sliding Friction (ÃŽ ¼k) Measure angle ÃŽ ¸ for sliding friction by using Aluminium tray Table 2.1: Aluminium tray Measure angle ÃŽ ¸ for sliding friction by using Brass tray Table 2.2: Brass tray Measure angle ÃŽ ¸ for sliding friction by using Nylon tray Table 2.3: Nylon tray Measure angle ÃŽ ¸ for sliding friction by using Ferado tray Table 2.4: Ferado tray 2.2.2: Following procedure is to verify the force required parallel to an inclined plane to move a body up the plane corresponds to the friction coefficient already found. First of all set the stainless steel plane horizontally at 10 slope. Place the towing cord and weight hanger in position to pull the tray up to the plane by placing any material tray at the lower end of plane. Add load to the hanger until the tray, given a slide push, slides slowly up the plane. Repeat the same procedure by applying 10N weight at angle 20 and 30. CHAPTER 3 CALCULATIONS AND RESULTS 3.1: Procedure 1 As we found angle above, now to find coefficient of static deflection, take tan ÃŽ ¸. For Aluminium (Tan15.8) = 0.28 For Brass (Tan14) = 0.25 For Nylon (Tan20) = 0.36 For Ferado (Tan18.8) = 0.34 Table 3.1: Coefficient of static deflection As we found angle above, now to find the coefficient of sliding friction, take tan ÃŽ ¸. For Aluminium (Tan10.8) = 0.19 For Brass (Tan15.1) = 0.27 For Nylon (Tan12.3) = 0.22 For Ferado (Tan13.7) = 0.24 Table 3.1: Coefficient of sliding friction Procedure 2: First of all find the normal force Normal Force = W.cosÃŽ ¸ Normal Force = 3.58.cos10Â ° Normal Force = 3.52 N Secondly find the Sliding force Sliding Force = p-(W.sinÃŽ ¸) Sliding Force = 1.2-(3.58.sin10Â °) Sliding Force = 0.58 N Now as we have both normal and sliding force, we can find Friction Coefficient ÃŽ ¼ Friction Coefficient = Sliding force / Normal force Friction Coefficient = 0.58 / 3.52 Friction Coefficient = 0.16 All the values were measured for angle 20Â ° and 30Â ° as shown in the table below. Table 4.1: Nevertheless, the additional 10N weight were added but the friction coefficient and angle will remain same as shown above in the table which proves that weight cannot change the angle and coefficient of friction. By converting mass of the tray into weight we can prove the experiment. W = mg W = 0.365*9.81 W = 3.58 N CHAPTER 4 ANALYSIS AND DISCUSSION Subsequently investigation in the data, we all observed that hypothesis is true, where the static along with kinetic friction is usually affected by the mass of body. The coefficient in the kinetic along with static friction is determined by materials used for each call surfaces. The coefficients will never always be bigger than 1 and the coefficient connected with kinetic friction is definitely more compact as opposed to among static friction for that identical scenario. The value of coefficient of friction is 0.18.The laboratory on the other hand, we all would come up with a vibrant mistake thats produced each of our kinetic friction importance unfeasible, as the importance for we all received ended up being caused by the tension pulling on the block. However, there were some systematic error occur while doing experiment. These errors were arisen due to string and hanger as they were not straight and each group member have different value while taking reading. CHAPTER 5 CONCLUSION The experiment was taken under good circumstances. However, errors can be reduce by overlapping the mistake that was take place in this experiment. This experiment could be done exactly the same as international standard if the following conditions apply on it. First of all make sure that the hanging masses do not move while adding additional weight on load hanger. This experiment will be really useful in the future to determine the coefficient of friction for different materials. REFERENCE: John, B Carl,T.F.T.F. Ross (2002).Mechanical Engineering Principles. Oxford: Taylor Francis. APPENDIX A CHAPTER 1.. CHAPTER 2.. CHPATER 3.. CHAPTER 4. Page 1 of 11

computer architecture :: essays papers

computer architecture Computer architecture covers the design of system software, such as the operating system (the program that controls the computer), as well as referring to the combination of hardware and basic software that links the machines on a computer network. Computer architecture refers to an entire structure and to the details needed to make it functional. Thus, computer architecture covers computer systems, microprocessors, circuits, and system programs. Typically the term does not refer to application programs, such as spreadsheets or word processing, which are required to perform a task but not to make the system run. In designing a computer system, architects consider five major elements that make up the system's hardware: the arithmetic/logic unit, control unit, memory, input, and output. The arithmetic/logic unit performs arithmetic and compares numerical values. The control unit directs the operation of the computer by taking the user instructions and transforming them into electrical signals that the computer's circuitry can understand. The combination of the arithmetic/logic unit and the control unit is called the central processing unit (CPU). The memory stores instructions and data. The input and output sections allow the computer to receive and send data, respectively. Different hardware architectures are required because of the specialized needs of systems and users. One user may need a system to display graphics extremely fast, while another system may have to be optimized for searching a database or conserving battery power in a laptop computer. In addition to the hardware design, the architects must consider what software programs will operate the system. Software, such as programming languages and operating systems, makes the details of the hardware architecture invisible to the user. For example, computers that use the C programming language or a UNIX operating system may appear the same from the user's viewpoint, although they use different hardware architectures. When a computer carries out an instruction, it proceeds through five steps. First, the control unit retrieves the instruction from memory—for example, an instruction to add two numbers. Second, the control unit decodes the instructions into electronic signals that control the computer. Third, the control unit fetches the data (the two numbers). Fourth, the arithmetic/logic unit performs the specific operation (the addition of the two numbers). Fifth, the control unit saves the result (the sum of the two numbers). Early computers used only simple instructions because the cost of electronics capable of carrying out complex instructions was high. As this cost decreased in the 1960s, more complicated instructions became possible. Complex instructions can save time because they make it unnecessary for the computer to retrieve additional instructions. For example, if seven operations are combined in one instruction, then six of

The Misery in Evil

There is a lot we can learn from infants. Infants have control over their emotions. When they feel hungry, they cry. When we feed them, they stop. They react the same way when dealing with such feelings and emotions such as nausea, sleep, and even anger. The children know how to let their emotions flow and as soon as the emotion is dealt with, they let the feelings go. As life becomes more complicated, people tend to forget how to let thing flow and then let them go. The older we get, the more we hold in the emotional baggage, allow ourselves to be possessed by them. Emily Bronte's Wuthering Heights tells a very good story of the consequences of holding emotions in without ever releasing them. The characters in the book are so deeply enveloped into their emotions that they create prisons for their minds. Their own acts of hate and unkindness create these prisons; prisons that won't let them escape from their misery. From a very early age, the seeds of hatred are planted into Hindley. When the orphan boy, Heathcliff is brought home to live with the Earnshaw family, Hindley becomes immediately jealous when the love of his father goes into Heathcliff. Along with his sister, Catherine, the two work together to ridicule the orphan child of his disabilities, mainly his illiteracy. When Hindley's father dies, he goes on to make Heathcliff's life miserable. He treats Heathcliff as one of the servants and terminates his education. The hatred is spread into Heathcliff as he vows to seek revenge on Hindley. While Hindley continued his abuse on Heathcliff, Catherine falls in love with the orphan child. However, Catherine had a personal ambition to find someone that would carry her away like an enchanted princess. She got this opportunity when she was allowed to enter the Linton house. Heathcliff, on the other hand, was told to go back home. While Catherine learned the ways of the rich, Heathcliff started his plan to seek revenge. One of the interesting aspects of the book is the fact that Heathcliff started off with the typical romantic hero. He was the orphan child, destined to rise above the standards. However, Bronte doesn't allow Heathcliff to transcend above his position in life. Throughout the novel, Heathcliff commits act of pure evil that is very hard for the reader to believe. He starts by killing a few dogs and goes on to create even more havoc. He tortures Isabella by testing her undying love for him. He even goes on to plan the use of his own child to seek revenge on his arch nemesis, Edgar Linton. All the while, the one thing that caused all of his pain, all of his misery, never stopped haunting him. Catherine died from the love she had for Heathcliff. Her acts of unkindness towards him led to her misery which would eventually lead to her death. Heathcliff could never bury Catherine and he felt like her ghost was always around watching him, waiting for him to join her. Heathcliff's ultimate revenge would take place by destroying the love between Hareton and the young Catherine. He tried to recreate a love triangle between his son Linton Heathcliff, the young Catherine, and Hareton. However, the young Catherine reminded Heathcliff of his love for her mother so much, that his desire to fulfill his act of revenge soon disappeared. When he finally realized this, his anger, his rage, turned to misery. Like his love before him, he let the misery take over, which would lead him to his own death. Heathcliff, along with many other characters in the story, were locked inside a cage they couldn't escape. The lock was composed of love, hatred, revenge and misery. For the second generation of children in the story (Heathcliff, Edgar Linton, Hindley, and Catherine), the self-made prisons made for some very miserable lives and depressing deaths.

What You Need to Know About the SAT Chemistry Subject Test

The SAT Chemistry Test or SAT Chemistry Subject Test is an optional single-subject test that you can take to showcase your understanding of chemistry. You might choose to take this test if you are applying to college to study science or engineering. The test is intended to help you with the college admission process. SAT Chemistry Test Basics Here are some important facts about the SAT Chemistry Subject Test: 60 minutes (one hour) long.85 multiple-choice questions.Offered October, November, December, January, May, and June.A calculator is not permitted.The periodic table is provided.All units are metric.Only simple numerical calculations are required.Scoring is from 200-800. (Note: You do not need to get all of the questions correct to get a perfect score.) It is expected that students will not have been exposed to every subject covered on the test. Recommended Preparation for the SAT Chemistry Test Year of algebraYear of general chemistry, college-prep level or higherSome lab experience Topics Covered by the SAT Chemistry Test The percentages given here are approximate. Structure of Matter (25%)States of Matter (16%)Types of Reactions (14%)Stoichiometry (14%)Descriptive Chemistry (12%)Laboratory (8%)Thermochemistry (6%)Equilibrium and Rates of Reactions (5%) This is not a memorization-type test. While students are expected to have an understanding of the fundamental concepts of chemistry, most of the test will involve organizing and interpreting information. With respect to the types of skills that will be needed to succeed with the SAT Chemistry Test, you can expect: 45% application of knowledge35% synthesis of knowledge20% fundamental knowledge and concepts