Roller+Coaster+Lab

=Conservation of Energy on a Roller Coaster= Date of Publication (Date of Most Recent Edits)


 * Participants**: Sean Hamilton, Ashley Murphy, Chelsea Hart
 * Purpose**: The purpose of this lab is to examine how mechanical energy (kinetic and potential energy) can be changed by outside forces.
 * Lab Documents**: [[file:Roller Coaster.doc]]

media type="file" key="RollerCoaster Movie Small.wmv" width="300" height="300"
 * Brief Description of Experiment**: In this experiment we observed a toy roller coaster. We took measurements of heights at certain points on the coaster to determine loss and gain of kinetic and potential energy. We measured the time it took the cart to get to each point on the roller coaster (premarked and measured points). We used the BeeSpi to record the velocity of the cart at the premarked points. With the data we collected and calculated we were able to create graphs showing the potential, kinetic, and mechanical energy of the system. We then used our observations to note the effects gravity had on our system, determining whether energy was conserved or not.
 * Data**:To find our data, the distance to each point was used. Then the speed of the cart at each point was recorded using a BeeSpi. The time it took for the cart to get from the top of the first drop to a point was measured using a stop watch. Then the data was inputted into LoggerPro and the graphs were formed using that data.

speed = distance / time || KE= 1/2*mass*velocity² ||
 * Sample Calculations:** Describe or reproduce any calculations that are performed during the experiment (other than averaging). For this lab, you should show calculations for total velocity (if you used video analysis), potential energy, kinetic energy, and a calculation of one external force.
 * //Speed calculation// || The speed in meters per second was calculated by taking the measured distance in meters and dividing by the time elapsed in seconds.
 * //Kinetic Energy// || Kinetic Energy is measured by multiplying one half times mass times velocity squared.

PEgravity= mass*9.8*height ||
 * Potential Energy || Potential Energy is measured by multiplying mass times gravity times height.

ME= KE + PEgravity ||
 * Mechanical Energy || Mechanical Energy is measured by adding Potential Energy and Kinetic Energy.


 * Results:** The result of this experiment is that energy was not conserved in this experiment. There were outside forces acting upon the system that caused energy to be lost. Gravity was the most apparent outside force that acted upon our system. Gravity caused the cart to be unable to completely conserve energy, which is why the motor was needed to bring the cart back to the top of the first big drop. If energy had been completely and totally conserved, the cart should have been able to be released at the top of that big drop and conserved energy throughout the experiment and been able to race to the top of the track without the motorized help.


 * Lab Questions**:
 * 1) What external forces did you identify as removing energy from the roller coaster system? Into what form of energy do you think the mechanical energy was converted via these forces? //Gravity was the external force we identified as removing energy from the system. For example, when the cart is going into the loop, gravity is working against it and the system loses potential energy; and also the amount of Kinetic Energy decreases faster than it would if there were no gravity. Decreases in either Kinetic Energy or Potential Energy means a decrease in Mechanical Energy.//
 * 2) What external forces did you identify as adding energy to the roller coaster system? From what form of energy do you think the mechanical energy was converted via these forces? //Gravity and the motor pulley on the big climb were adding energy to the system. Gravity adds to the Mechanical Energy by pulling down on the cart, and increasing its velocity, when it is coming out of the loop. This increases its Kinetic Energy, and also its Potential Energy. The motor pulley is adding Potential Energy when the cart is on the incline because when the cart exits the back loop, there isn't enough energy for it to go over the hill, but the pulley adds Potential Energy so that it can.//
 * 3) Break the motion of the coaster into 4 pieces as described below. What fraction of the total mechanical energy from the top of the coaster was lost in:
 * 4) The first big drop? //113.866 / 78110.779 * 100 = 0.15 % of ME lost//
 * 5) The entrance to the loop? //18429.357 / 78110.779 * 100 = 23.59 %// //of ME lost//
 * 6) The exit of the loop? 171.049 / 78110.779 * 100 = 0//.22 % of ME lost//
 * 7) The back turn? //9332.06 / 78110.779 * 100 = 11.95 % of ME lost//
 * 8) At what point in the motion of the roller coaster was mechanical energy being dissipated (lost from the system) most quickly with respect to distance traveled? How about with respect to time? //The big climb is where the Mechanical energy was lost most quickly with respect to distance traveled. The motor was necessary to move the cart, and so it lost energy the most at the climb. The most Mechanical Energy lost with respect to time was on the climb as well. Because it takes the most time to go over the hill, any energy the cart had was lost, but only a small amount was added from the pulley. Therefore, the cart loses the most Mechanical Energy on the climb, with respect to both time and distance.//


 * Conclusion**: The purpose of the lab was to observe the Law of Conservation of Energy in a toy roller coaster. The experiment produced valid and reproducible results in that if someone was to repeat this lab using the equations for Kinetic Energy, Potential Energy, and Mechanical Energy they would end up with the same results: that energy is not conserved in the system of a toy roller coaster. An improvement on this experiment would be to measure the speed from each point in a different way. Using the BeeSpi was effective, but not in the best way possible. Though it did measure the speed at each point, a better way to calculate it would be to use the distance to each point, and the time it took to get to each point. By using these two numbers, it would be more accurate. It would also be more accurate because the BeeSpi was difficult to use in some areas of the coaster, and that used time and it didn't seem as if it would be more accurate than to calculate it using LoggerPro after the data is inputted into the program.