# phys221 lab 6 report.pdf - Experiment 6 The Coefficient of...

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Experiment 6: The Coefficient of Friction
Abstract- The objective of this lab was to measure the coefficients of static and kinetic friction between a wooden block and a wooden plane. The equipment used included the wooden block and plane, the LABPRO with force probe, triple beam balance, masses, and a pulley. The procedure proceeded by calibrating the force probe and weighing the mass of the wooden block, and using that to begin measuring the static and kinetic friction with addition mass on the wooden block. Then we found the coefficients using two other methods- the angle of repose method and the constant velocity methods. The subsequent results show that the graphical method is a more accurate way to find the coefficients of friction. Primary sources of uncertainties were systematic and human errors. Results- Coefficients of Friction Force (calculated) = 4.34 N Force (measured) = 4.61 N Percent error = 6.22% Sample Calculations- -Force = mg(µkcosθ+ sinθ) Fp= .199(9.8)(0.2102cos(30) + sin(30)) = 4.34 N -µ= tanθµ= tan(20) = 0.364 -% difference = |v1 –v2| / [.5(v1 + v2)] * 100 |0.2918 – 0.2101| / [0.5 (0.2918 + 0.2101)] * 100 = 32.51% -% error = | measured value – true value | / true value *100 | 4.61 – 4.34 | / 4.34 * 100 = 6.22% µsµkGraphical Method0.29180.2102Angle of Repose Method0.364 / 0.384N/AConstant Velocity MethodN/A0.231 / 0.222Percent difference22.02% / 27.3%9.4% / 5.46%
Discussion of Results- The objective of this experiment was to measure the coefficients of static and kinetic friction. We met the objective by using different methods and comparing the results
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