Author: Zach Christoff
Lab Partner: Daniel Baka
Date: 12/11/15
Lab Partner: Daniel Baka
Date: 12/11/15
Purpose
The purpose is to investigate and verify the Law of Conservation of Energy.
Theory
The Law of Conservation of Energy states that energy cannot be created or destroyed, but it can be transferred or transformed from one state to another. Therefore, energy in a system is never gained or lost. This lab will prove this law by demonstrating that kinetic energy will equal elastic energy. However, kinetic energy often changes to thermal energy, so there will be slight differences in the energy amounts.
Experimental Technique
Part 1
For the first part of the lab, I must find a spring constant, k, that will be used later in the lab to calculate energy. A cart, with a spring (black paint) surrounding a small plastic rod, was hooked onto a force sensor. Using DataStudio, the force was measured at different increments along the plane, all separated by .005 m. Ten different values were created in order to create a line with as much correlation as possible.
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Part 2
For the second part of the lab, velocity must be measured in order to calculate energy. This was done by first measuring the elongation of the spring, x. This is found by subtracting the length of the spring fully compressed from the length of the spring uncompressed. Note: the coils cannot be touching each other or else the results would be skewed.
Once the spring was fully compressed, the plastic rod was placed through two gates, were a pin was placed (far left of the picture) to hold it in place. A string was then tied to the pin which would allow for the cart to be released smoothly. DataStudio measured the velocity of the cart as it passed through the photogate, and this was repeated six times. However, mass was varied each time. |
Data
Part 1
Part 2
Since the spring constant, k, was found, elastic energy was able to be found. With the measurements made in DataStudio, kinetic energy can be found too. With kinetic and elastic energy calculated, I am able to compare the two and investigate whether or not the Law of Conservation of Energy holds.
Analysis
Conclusion
For the first part of the lab, I found the spring constant by slowing inching a cart up a ruler. For the second part of the lab, I found velocity and mass which allowed me to find elastic energy and kinetic energy. I then compared them by using a percent difference formula. My highest percent difference was 5.5%, and I even had one that was only 0.1% difference.
Some errors include errors from the equipment, as it is a very sensitive device moving only a short distance at a short velocity. Also, probably one the biggest contributors of error is the loss of heat as thermal energy. Energy is perfectly conserved, but not through only the change of kinetic and elastic energy. Thermal energy lost take away from the transfer of energy, but the results from this lab further prove the Law of Conservation of Energy.
Some errors include errors from the equipment, as it is a very sensitive device moving only a short distance at a short velocity. Also, probably one the biggest contributors of error is the loss of heat as thermal energy. Energy is perfectly conserved, but not through only the change of kinetic and elastic energy. Thermal energy lost take away from the transfer of energy, but the results from this lab further prove the Law of Conservation of Energy.
References
Giancoli, Douglas C. Physics: Principles with Applications. 5th ed. Upper Saddle River, N.J.: Prentice Hall, 1998. Print.