1. The roughness of the surface of the objects and the plane/track used in the experiment should be in even condition. Meaning the experimenter should check the roughness by touching the surfaces. For instance, in this experiment, a piece of sand paper is wrapped to the wooden block (to investigate the coefficient of the sand paper surface due to the plane surface which is wood). The sand paper should be the one that has not been used before. This is due to the fact that even though the sand paper can be used for many times, however the roughness is already not the same.
2. There might be a very large range of the uncertainty of the height of the lifted end of the plane. This is due to the action of elevating the end of the plane which is done manually by the experimenter. As to reduce to error, the position of the plane when the object starts to slide is held still using a retort stand.
This is done while taking the measurement of the height.
3. In determining the coefficient of the static friction, the formula of = tan can be used. Nevertheless, since the method used in this portion of experiment allows the experimenter to choose between two options which are either to use the above equation of to use the ratio of the height of the elevated end of the plane to the horizontal length of the plane. The experimenter choose to use the ratio as error is minimized, compared to the equation.
Conclusion:
Part A : The greater the coefficient, the rougher the surfaces. The coefficients are different between different surfaces. This is due to the fact that if the object is having bigger angle of inclination, it shows that the coefficient is bigger. Thus, it can be concluded that the surfaces are rougher. Part B : The greater the coefficient, the rougher the surfaces. The coefficients are different between different surfaces. This is due to the fact that if the object is having bigger force to be applied in order to move it, it shows that the coefficient is bigger. Thus, it can be concluded that the surfaces are rougher. Contribution: 1. I suggested to use the acceleration method to determine the kinetic friction 2. I recorded the results obtained. 3. I elevated the track.
References:
http://hyperphysics.phy-astr.gsu.edu