Energy Lab
Name: Kyle Collins
Lab Partner: Parker Fairchild
Date: 16 January 2015
Purpose: The purpose of this lab is to examine the relationship between elastic energy and kinetic energy.
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Theory, Part A: According to Hooke's Law, F=kx, where F equals force, k is the spring constant, and x is the distance that the spring was compressed. This can be arranged as k=F/x. Position and force can also be plotted on a scatter plot, where the slope of the line is equal to the spring constant k.
Experimental Technique, Part A: A cart was placed on a track, and a spring backstop was attached to the track. On the cart was an attachment to hold the spring needed for the experiment. The spring attachment was pushed through the hole in the backstop, and a force sensor was mounted to the back end of the spring attachment. This entire system was pulled in .5cm increments by the force sensor, and the amount of spring compression (equal to the distance pulled) and force readings were recorded at each position. These were plotted on a scatter plot in order to find k.
Lab Partner: Parker Fairchild
Date: 16 January 2015
Purpose: The purpose of this lab is to examine the relationship between elastic energy and kinetic energy.
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Theory, Part A: According to Hooke's Law, F=kx, where F equals force, k is the spring constant, and x is the distance that the spring was compressed. This can be arranged as k=F/x. Position and force can also be plotted on a scatter plot, where the slope of the line is equal to the spring constant k.
Experimental Technique, Part A: A cart was placed on a track, and a spring backstop was attached to the track. On the cart was an attachment to hold the spring needed for the experiment. The spring attachment was pushed through the hole in the backstop, and a force sensor was mounted to the back end of the spring attachment. This entire system was pulled in .5cm increments by the force sensor, and the amount of spring compression (equal to the distance pulled) and force readings were recorded at each position. These were plotted on a scatter plot in order to find k.
Data and Analysis: The spring constant of the blue spring was found to be 104.98N/m. This was found by plotting all data points and checking the slope of the best-fit line. The R-value is also very high, indicating a very precise measurement.
Conclusion, Part A: The high R-value indicates that this spring constant is very close to the actual value. As for error, some was alleviated by placing index cards underneath the force sensor in order to make it level with the cart. Parallax error was also corrected for by reading the scale on the track with one eye open directly from above.
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Theory, Part B: In energy considerations, energy can be neither created nor destroyed. This is known as the Law of Conservation of Energy.
Experimental Technique, Part B: For the second part of this experiment, two spring backstops, the cart with all previous attachments, a photogate, and a removable flag were needed. The cart was pulled back a set distance and then released. By using the Law of Conservation of Energy, the energy before release was set equal to the energy after release, and was solved for velocity. Velocity was also measured in DataStudio, and compared to the calculated value using a percent difference equation.
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Theory, Part B: In energy considerations, energy can be neither created nor destroyed. This is known as the Law of Conservation of Energy.
Experimental Technique, Part B: For the second part of this experiment, two spring backstops, the cart with all previous attachments, a photogate, and a removable flag were needed. The cart was pulled back a set distance and then released. By using the Law of Conservation of Energy, the energy before release was set equal to the energy after release, and was solved for velocity. Velocity was also measured in DataStudio, and compared to the calculated value using a percent difference equation.
Data and Analysis, Part B: The two spring backstops were set 7cm, or .07m, apart. This was the value used for x. By using the shortest flag on the cart in conjunction with DataStudio, an average velocity of .87m/s was measured. Using energy considerations, the velocity was determined to .97m/s, approximately an 11% difference.
Conclusion, Part B: The percent error was probably as high as it is because thermal energy produced from the motion of the cart was not accounted for. This would have needed to be added to the side of the energy consideration with kinetic energy, greatly complicating the solution. In addition the rod that the spring attached to likely scraped against the spring backstops, creating friction and slowing down the cart.