Coefficient of Friction

Coefficient of Friction Lab Abstract The resisted force that acted along the tangent of two surfaces that were in contact was called friction. Friction was opposed to motion, and it acted in the opposite direction, where the surface of the object slid against the surface of the other object. The two types of friction that exist were called static friction and kinetic friction. When two surfaces are at rest with each other, but a push is caused to convey one of the surfaces to slide over the other was called static friction.However, the friction that was used in the lab was kinetic friction. Kinetic friction occurred when two surface were moving with contact to each other. The coefficient of kinetic friction is a constant shown as ? k. The kinetic frictional force (fk) was given by the following equation: (fk= ? kN), where N represented the normal force, which was the force that each body exerts on the other body, and acts perpendicular to each surface. The way that friction force is calculated is by the followed calculation: Ff=? FN, where (? ) was the coefficient of friction and (FN) was the normal force.Now in order to pinpoint the force of friction, the coefficient of friction should be figured out first. Now the way that the coefficient of friction was retrieved, the tension force (FT) was divided by the weight (Fg). An inclined plane that has an angle of ? was adjusted as shown in the following diagram: 2 If the block was placed on the plane, and the angle was slowly increased, the block would have began to slip at some angle. Now the normal force (N) acted perpendicularly to the plane, and a component of the weight of the block, acted in the opposite direction.Though when the angle is increased, the more force it took for the block to slide against another surface. So as the angle was increased, the friction cultivates, but when the angles decreased, so did the friction. 1 Now some of the factors that can affect friction are the body surfaces. For the fri ction depends on the smoothness of the surface where the objects have touched. Now with the smoothness only to a degree has made friction decrease. Friction never depended on the amount of surface that there was given, but it does depend on the magnitude of forces holding the bodies. 1Methods Inclined plane was placed at a zero angle position so the pulley protrudes over the table edge Mass of the wooden block was determined to the nearest tenth of a gram. String was attached to the wooden block, over the pulley and to the weight of the hanger. Orientation of the string was adjusted so that it was parallel to the plane. The planes have differed in their smoothness. Surface must clean and dry. Masses were added to the hanger until the wooden block moved at constant velocity after it was tapped lightly. The total weight (FT) was recorded in the table for data. The result of the weight hangers and the masses on the hangers was total force pulling. All weights are in the proper units (N ewtons)). By have added different masses on top of the wooden block (Fg), step 4 was repeated for several different total weights. Plane must be inclined at some angle between five and twenty degrees. Step 4 was repeated. Total weight was recorded. This was the tension (FT) at angle ?. Investigation was continued by an additional experiment that was planned, which compared how the angle affected the coefficient of friction.(An extra table must be included on this data. Data Analysis OFg(block)=FNFT(force of g on masses)=N ? 0328g=3. 2144N1. 4N. 44 0351. 8g=3. 44764N1. 4N. 41 0540. 9g=5. 3N1. 5N. 28 0573. 8g=5. 6N1. 7N. 30 0614g=6. 0N1. 9N. 32 0611. 4g=6. 5N1. 9N. 29 5 20 degreesF_gF_NActualTheoreticalAverage 153283. 2N2. 1N1. 9N0. 34 10368. 63. 6N1. 6N1. 8N0. 34 Sample Calculations: Sample calculation for Force in Newtons for Fg: 328(0. 001)(9. 8)=3. 2N Sample calculation for  µ: (FT/Fg)=1. 4/3. 2=. 44 Percent errors: Percent error for 15? :(|1. 9-2. 1|)/1. 9 x 100=10. 5% Percent error for 10? :(|1. 8-1. 6|)/1. 8 X 100=11. % Discussion The computed theoretical value of FT was slightly off for both 10 &15 degrees. The resulted percent error for 10? was just slightly over 11% and for 15? it was a bit over 10%. The outcomes could have been different due to the fact of friction, which could have not been calculated correctly when the block had faultless constant velocity, however, the values were nearly related. Now the relationships between the graphs shown above seems to prove that the variables which are indicated seem to be directly proportional to each other and the graphs, â€Å"†Force vs.Coefficient of Friction† & â€Å"Force of Block vs. Force of Tension are very similar. † It seems to be that the block was conveying at a constant speed in order to have given calculated the friction precisely. Now if the block were not to be moving with constant velocity then friction wouldn’t be steady, and if it wasn’t then there was n ot an precise calculation for the coefficient of friction. Now not having a smooth surface can cause an error, which causes the block to decrease and speed up. Now in order to repair this error, there must be a real smoothed surface where the experiment will be performed.The string sticking on to the pulley can be know as another error because it could cause the movement of the block not to be smooth as it would be predicted in this experiment. The solution of this error would be to put something on the string, so that it may slide efficiently. Conclusion The conclusion of this experiment seems that everything seems to be similar and in order. The percent errors that was given for 10? was 11. 1% and the percent error for 15? was 10. 5%, meaning that the theoretical value and actual value for the tension were nearly the same. Now the average value for the coefficient of friction ( µ) was 0. 34.