Horizontal circular motion

According to the data collection and processing section, the experimental result for the mass of the weight hanger (vertical mass) is 330. 28g with a percent uncertainty of ±7. 3% or ±24. 11g as an absolute uncertainty. At a percent error standpoint, the experimental result of 330. 28g compared to the actual mass of the weight hanger results an 11. 85% percent error, compared to the percent uncertainty of 7. 3%, percent error is smaller by 4. 55%. The calculated value does not lie within the scope of the uncertainties; therefore the experimental value derived is inaccurate.

The large percent uncertainty and percent error corroborates that the defective design of the experiment have significantly impacted the outcomes of the lab, both systematic and random errors contributed greatly to the percent error of the experimental result. The uncertainty errors throughout the lab has been high, one of the main contributors to the large error is the time required uncertainty, the most significant factor that contribute to this uncertainty is due to the very nature of the stopper swing, at around 9.

3m/s it is extremely difficult or perhaps impossible for the naked to judge the exact 10 revolutions made by the stopper and react to it at the same time, furthermore, the stopper’s speed must vary for every trial because the swinging motion is controlled manually, unless the swinging technique is fully mastered, the force applied to swing the glass tube should always be different, therefore resulting a significant systematic error.

The second flaw of the experiment comes from two assumptions made in the lab, one of them being that the glass tube is frictionless when in contact with the string in the swinging motion of the rubber stopper, although the glass tube is to reduce the friction between the two objects’ friction to a minimum, but the design and equipment used in the lab is limited, in reality, there must have been thermal energy lost in the process.

The second assumption is that the rubber stopper travelled in perfect horizontal motion with no x directions to it, this assumption was made to help aid the calculations made and make sense of the centripetal force definition in horizontal motion, in reality the perfect swing could never have happened due to the very nature of the manually control, in order to eliminate the x direction made by the swinging stopper, the force applied to the tube would have to be constant with just the right amount at all timed intervals.

Throughout the experiment, the fatigue of the arm of the experimentalists was evident; this could have contributed even more to the x direction of the swing. The two assumptions above could have caused major discrepancies during the course of the lab and could have potentially contributed to most of the percent errors in the experimental result.

The last flaw in this experiment is the measurement of the radius; this also fall in the category for with the problem of manually control the swing and assumptions, since the radius used in the centripetal force formula, we have to measure the radius before every trial, as the data collection demonstrates, the length of the radius decreases over time, this may be due to the effects of the swinging motion on the twirling of the string and have somewhat of an effect on the result as the string can elongate during the performance of the experiment as well.

The second flaw from the radius is that the assumption is made that it will always be measured from the clip to the tip of the rubber stopper. In reality, the clip can only come infinitely close to the glass tube for the experiment to work (because they cannot touch), and because the motion of the swing is controlled manually, it’s almost certain that every radius during the course of the lab in each trial will vary, which can have significant impact on the result.

The use of a more precise stop watch would be a valuable tool, because the stopper travels at a very fast speed, as the data processing shows, one revolution of the stopper takes an average of 0. 35 second, the time relates directly to the speed (v) of the stopper, and this would ultimately affect the result on the centripetal force and the experimental result of the mass, therefore determining the period of the stopper as accurate as possible is crucial for the accuracy of the experiment.

Secondly, the manual control of the swing has caused chaos in terms of systematic errors the experiment, to solve this problem realistically; we could use something similar to the mechanism of a pedal system on a bike, we can place it sideways and attach the glass tube onto one of the pedals and spin the other manually by hand, this could reduce the x direction made by the stopper to a minimum in the most affordable way, and would give us a better result.

To reduce the twirl and friction of the string, we could use a softer string with fewer threads bind together; the softness of the string will reduce the friction to a minimum, with fewer threads bind together in the string, the twirl will be reduced to a minimum, lowering the systematic errors. All of the improvements about relates to the systematic errors as the percent error is larger compared to the percent uncertainty, they will reduce the systematic errors to a maximum and ensure better results.

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