Lab 13: Magnetic Potential Energy Lab
May Soe Moe
Lab Partners: Ben Chen, Steven Castro
17-April-2017
Objective: To verify that the conservation of energy applies to the system we came up for this lab.
Introduction: By turning on a vacuum, the air glider would glide along the air track and move toward the motion detector. Two magnets with same polarity at the end of the cart and the air track are attached. Since they have the same polarity, once the glider reaches to the end of the track, the magnet at the end would repel the glider, causing the glider to move to other direction of the motion. In this lab, we would like to show that our kinetic energy and potential magnetic energy of our apparatus is constant, therefore, energy is conserved. The problem of this lab was that we did not have an equation for magnetic potential energy. Therefore, by plotting a graph of Force vs. separation distance graph, we would get the power fit to the graph to get that equation that represents the magnetic potential energy. Once we get our equation for magnetic potential energy, we would use that as our model to figure out if our conservation of energy in our system or set up is conserved or not.
Experimental Procedure:
Apparatus:
(1) The set up was already done by the professor.
(2) Air glider is used to move along an air track when the air is turned on. There are numerous holes in the air track. Through those holes, air would push up the glider, making it not really in contact with the track. That makes the track frictionless surface.
(3) One magnet was sticked to the end of the glider and another was sticked at the end of the air track. What would happen with this lab is that the glider would move toward the motion detector when air is turned on. When it reaches to the end of the track, the glider would bounce off and move to opposite direction due to the magnets. The magnets have same polarity-- like poles repel, and unlike poles attract each other. Because the magnets' poles are the same, it repelled and let the glider bounce off to other direction. This is almost the same as the spring; the spring would pull back an object when it is stretched to a certain distance and let go.
(4) Here, during the repel, we saw that the glider did not go to the very end of the track nor did it touch the magnet. There was a distance in between two magnets, which we called separation distance r. Like our previous labs before, we would approach this lab to find the force vs. position graph.
(5) We cannot find the force between the magnets directly. Therefore, what we used as a force between the two magnets was by representing force as mgsinθ since the glider was going in the x-direction. We would put the air track at a certain angle by adding books underneath.
(6) We used bubble level app from our phones to measure the angle of the air track.
(7) Then how do we get our position? Our position function was the distance between the glider and the motion sensor minus separation distance r between two magnets.
(8) Once we were ready with the setup, we gave a slight push to the glider after turning the air on. We started collecting the data and graphed our force vs. separation distance r graph.
(9) We repeated this procedure a few times by adding books underneath the track to raise the angle.
And we collected new sets of data at those different angles.
Verifying the Conservation of Energy
May Soe Moe
Lab Partners: Ben Chen, Steven Castro
17-April-2017
Objective: To verify that the conservation of energy applies to the system we came up for this lab.
Introduction: By turning on a vacuum, the air glider would glide along the air track and move toward the motion detector. Two magnets with same polarity at the end of the cart and the air track are attached. Since they have the same polarity, once the glider reaches to the end of the track, the magnet at the end would repel the glider, causing the glider to move to other direction of the motion. In this lab, we would like to show that our kinetic energy and potential magnetic energy of our apparatus is constant, therefore, energy is conserved. The problem of this lab was that we did not have an equation for magnetic potential energy. Therefore, by plotting a graph of Force vs. separation distance graph, we would get the power fit to the graph to get that equation that represents the magnetic potential energy. Once we get our equation for magnetic potential energy, we would use that as our model to figure out if our conservation of energy in our system or set up is conserved or not.
Experimental Procedure:
Apparatus:
 |
| Our Apparatus for this lab |
(2) Air glider is used to move along an air track when the air is turned on. There are numerous holes in the air track. Through those holes, air would push up the glider, making it not really in contact with the track. That makes the track frictionless surface.
(3) One magnet was sticked to the end of the glider and another was sticked at the end of the air track. What would happen with this lab is that the glider would move toward the motion detector when air is turned on. When it reaches to the end of the track, the glider would bounce off and move to opposite direction due to the magnets. The magnets have same polarity-- like poles repel, and unlike poles attract each other. Because the magnets' poles are the same, it repelled and let the glider bounce off to other direction. This is almost the same as the spring; the spring would pull back an object when it is stretched to a certain distance and let go.
(4) Here, during the repel, we saw that the glider did not go to the very end of the track nor did it touch the magnet. There was a distance in between two magnets, which we called separation distance r. Like our previous labs before, we would approach this lab to find the force vs. position graph.
 |
(6) We used bubble level app from our phones to measure the angle of the air track.
(7) Then how do we get our position? Our position function was the distance between the glider and the motion sensor minus separation distance r between two magnets.
(8) Once we were ready with the setup, we gave a slight push to the glider after turning the air on. We started collecting the data and graphed our force vs. separation distance r graph.
(9) We repeated this procedure a few times by adding books underneath the track to raise the angle.
And we collected new sets of data at those different angles.
(10) With our collected data, we graphed a velocity vs. time graph, and a position vs. time graph to help us with finding the kinetic energy.
 |
| Position vs. Time and Velocity vs. Time graph to help us find Kinetic Energy |
(11) We put in all of our datas including our angles and separation distance r values. Then we graphed a force vs. separation distance r graph.
 |
| This is how our force vs. separation of r graph should looks like. |
 |
| Position and Angle are collected data and Force is calculated data. |
 |
| How we calculated force for various angles |
 |
| Our graph of Force vs. separation distance |
(12) Doing the powerfit of the force vs. separation distance gave us a function that will represent the magnetic potential energy after doing the integral of this function.
(13) We knew that negative integral of the force and distance function equals to potential energy. Therefore, we integrated the function we got from the graph to get us the function of magnetic potential energy.
 |
| Integrating the function from the graph. U represents magnetic potential energy |
Verifying the Conservation of Energy
We would try to verify the conservation of energy by putting kinetic energy, magnetic potential energy and the total energy of the system as a function of time onto one graph.
 |
| Kinetic Energy, Magnetic Potential Energy and Total Energy in one graph |
 |
| This is how our Kinetic energy, magnetic potential energy, and total energy should looks like. (standard graph) |
Conclusion: By comparing the standard graph and our resulted graph, we can see that they are quite similar, but not constant. We assumed that there was no friction force acting on the glider for our system. But when we assumed there is no friction between two surfaces, the graph should come out like the standard graph. But since it did not come out to be smooth line or curve, we could be sure that there was kinetic friction acting on the glider during the time of glider moving along the track. Although our graph was not smooth, kinetic energy and total energy stayed in that range, without moving up or down too much. Therefore, we can say conservation of energy for our system stayed conserved.
No comments:
Post a Comment