performed as carefully as others, and it was difficult to gradually increase the amount of force until the object started moving, especially at the lower weights. For that reason, there could have been an increased error with results at lower weights. There were 3 Pasco trays with surfaces of cork, felt and plastic. However, we only performed the experiment with one tray. Had we experimented with all three, it is likely that the order for the coefficients of friction would have been cork, felt, and then plastic. It has been proven through other experimentation that cork usually has the highest coefficient of friction followed by felt and plastic. Looking at the Force v. time graph, during time A, the object has increasing static frictional force, and at point B, the maximum static frictional force is reached. From time A to B,
the object is not yet moving, since the applied force has not overtaken the frictional force. After B, C occurs, when the object starts moving and the coefficient of friction becomes kinetic, less than the maximum static friction coefficient. At D, the object has settled into moving at a constant speed, and as shown, the applied force is constant as well. The normal force on the bottom surface did not affect the coefficient of static and kinetic frictions. Coefficient of static and kinetic friction depends entirely on the types of surfaces being rubbed together, not the weight of rubbing them together, though the frictional force is impacted by the normal force, as shown in the equations Ffs= μsFN and Ffk= μkFN. The values of the coefficients of static and kinetic friction have an observable relationship. Static friction increases up to a maximum force before movement. Maximum coefficient of static friction is always greater than kinetic friction of a constant speed. 6. ConclusionAs this lab is concluded, I now know how to test for the static and kinetic frictional forcesusing a force sensor. I also know how to measure the coefficients of static and kinetic friction between surfaces and how to calculate and analyze forces using a FBD. However, we probably failed some objectives of the lab in performing the 2ndpart of the experiment incorrectly. But since I performed the theoretical calculations and understand how they work, I have come through with an understanding about how to accurately perform the lab, were it to be done again and of the underlying concepts the lab tries to teach. I would be sure to look more closely at the procedure and take precautionary measures that nothing is missed. For this lab, we performed 5 trials each for Part 1 and 2 of the lab to observe the relationship between static and kinetic frictional forces. Using graphs of frictional force v.
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