13-Apr-2015 Magnetic Potential Energy

Purpose
There was two purposes to this lab was to determine the conservation of energy for a magnetic system.

Experiment
The set up for this experiment is an air track with an air glider on it and a motion sensor on the end of the track on where the magnet is. For the first part of the lab we raise the track to different angles, then let the glider get as close to the end of the track as possible until it stops. We do this process six times so we get six sets of data.

We then take the six sets of data and graph them in logger pro, and from that graph we power fit it. Next we enter a new calculated column for the force which in this case would be gravity (mgsinθ) and then graph the force against the separation distance. Since we know that the area under the curve for a force vs position graph is work we can then find an equation of the line and integrate it. We use a power fit curve for the line since it fits the cure the best and the equation given is the equation for the magnetic force, and then we integrate that force to get the equation for the magnetic potential energy. In our case however we strike through the last point because it was too far off from the curve making it an outlier.

Now that we have found the equation for the magnetic potential energy we can now start the second part of the experiment. The second part of the experiment has the same set up as the first part, except that instead of being raised at and angle it is left leveled. We then start the glider at the end of the track and give it a push towards the magnet while recording the collision.

After the data collection is over we created new calculated columns for kinetic energy, separation, magnetic potential energy, and total energy. For separation we take the position that the motion detector reads and subtract it from the difference between the distance between the position the motion senor reads and the distance between the two magnets. We then graph all the energies together on the y-axis against time to compare and see if energy is indeed conserved within the system.

From our graph we can see energy is conserved by in that as the kinetic energy decreases it is becoming magnetic potential energy thus the magnetic potential energy increases. The total energy reflects that by being a constant line across; however in the above graph it is hard to see since the range are very small, but if we increased the ranged from 0-0.02 to 0-0.4 we can see that it relatively a straight line.

The reason that the total energy is slightly tilted when we zoomed out would be cause by error when we calculated magnetic potential energy. The cause for this error would be from the uncertainty that in the ruler used, the uncertainties that logger pro gave us when we generated the graph magnetic force, and the uncertainties of the phone when measuring the angle. Another source of error would be in part two of the lab there was interference with the motion sensor as can be seen by the kinetic energy line. The cause for this error could be from interference from the the motion sensor bouncing off part of the glider instead of only the steel plate, another reason would be that there was some friction on the track.