Physics coursework Essay Example for Free

Physics coursework Essay To make it clearer, I need to provide some graphs to my report, which would show much clearer what is happening in the experiments. On the table I have written, snapped for the end result of each experiment. This literally means that the wire has snapped at this point. Unfortunately one of the experiments snapped before the other two, this information would prove to me that either the experiment was carried out differently, poorly, or just that the wire was in different conditions. Analysis Firstly a major factor that I investigated which I believed would affect the distance that the wire stretched, was the time period between applying weights. If I applied all the weights at the same time it would snap quickly and results that I would have received would have contradicted each other, by this I mean when each weight is added it wouldnt have enough time to stretch the wire to its full potential. To resolve this I applied the weight on a two minute time period, however considering that the first 70 or so Newtons didnt have much effect on the wire, I applied them at a slightly faster rate. The following table shows the relationship between the mass and distance stretched: As you can clearly see from the graph, the first 50 Newtons have no effect on the wire, between 50 180 Newtons little change is occurring, but from that point the wire is experiencing large amounts of strain. Small stress will cause the copper wire to stretch. Remove the stress and it returns to its original dimensions. This is known as elastic deformation. If the stress is increased too far and it passes the point of elastic deformation, the wire snaps. However at this point of elastic deformation the wire yields, from this point the wire begins to deform, this is now plastic deformation. The information that I now have enables me to calculate other such factors of the physics of the experiment. I can work out stress and strain levels, and then from that, the youngs modulus of the wire. The youngs modulus of the wire tells me how flexible or stretchy the wire is. Calculations: Stress = Load / (cross sectional area of the wire) Cross sectional area of the wire = pie x r (squared) Cross sectional area of the wire = 0. 1075mm(squared) Stress = x / 0. 1075 Strain = Extension / Original Length Strain = x / 300(cm) Youngs Modulus = Stress / Strain I can add the stress, strain and youngs modulus values to my table: Mass Distance (mm) (N) Exp 1 Exp 2 Exp 3 Average Strain Stress Youngs Modulus  Snapped Snapped. The information I have received from the table will then enable me to provide the conclusion with such arguments as youngs modulus graphs: The stress-strain graph for the copper wire is pretty much a straight line, up to the point where it fractures. At the point where it fractures the wire experiences plastic deformation this is when the wire cannot be shaped back into its original counterpart. To show the stress and strain levels acting on the wire most effectively it would be clearer to draw a graph: The graph above shows the elastic region, the plastic region (extension uniform along length) and the plastic region (necking has begun). Conclusion From these results and the way that I have interpreted them I can conclude that the wire behaves to the weight applied to it, in firstly an elastic behavior pattern, then finally in a plastic behavior pattern, depending on how much weight is applied. The more weight applied to the wire, the closer it gets to plastic behavior and eventually snapping. Therefore stress and strain levels upon the wire at these points are behaving differently resulting in a youngs modulus graph, which proves the elastic/plastic behavior patterns. Some of the results that were recorded may have been affected by human errors such as applying the weights drastically and measuring the distances that wire has stretched incorrectly, but however carrying out the experiment in great detail would take large amounts of time, which would not enable me to compile three experiments and an average. Ways that my experiment could have been improved: if a weight applying mechanism were used, it would prevent the weights causing noticeable differences to the distance that the wire has stretched. Another problem, which I experienced with the weights, was the fact that more than one slotted mass hook to be applied to the wire. If a device was prepared so that weights were added to the slotted mass alternately to prevent handling the weight to apply the mass. If I were to carry out the experiment again, I would use a thinner wire, or one with a lower tensile strength. This would mean that less weight is to be applied to the wire. I would do this because if you look back at my results the first 60 or 70 Newtons dont affect the wire at all. If the wire is going to snap sooner, it will mean that the wire will stretch less. George Buse Mr Pellet Physics Coursework 1 Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.