Lab 9: circuits

Lab: 9 circuits

To experiment with and learn more about circuits we hooked up an ammeter to a power source and began experimenting with how resistors, light bulbs, and changing the amount of resistors affected the voltage going through the wires. After experimenting with a light bulb we measured the voltage of the wire after it had gone through the light bulb and found that voltage seemed to increase linearly with the amps, or as we increased the power the brighter the light bulb seemed to get, logically this made sense. Thus we made the argument that all of the system would follow the same principle.

This however proved untrue when we added in a second resistor. After adding a second resistor we found that the voltage began to experience an exponential growth. This seemed to be based on how and when the resistors began absorbing the charge and how much began to go through at a time. As the amps increased the voltage being stopped and regulated by the resistors seemed to be mixed up by the second resistor, changing the voltage increase from a linear one to an exponential one.

Thus our original prediction was proven false, the information managed to both contradict and support our original experiment. The voltage in the current did increase based on the amps provided, but were limited in differing amounts based on the amount of resistors in the wiring.

Problems and issues

an unfortunate problem we had was that the voltage would change roughly based on how much pressure and where we placed the attaching clamps on the resistor or how tightly we held the wires to the light bulb. this could have disrupted some of out data an information, but not likely enough to disrupt the entire results.

Lab 8: Electrostatics

Lab 8: Electrostatics

There are many ways to test Electrostatics, but some of the best ways to test and explain them is through Pith balls and electroscopes. Pith balls are two lightweight “pith” balls suspended from the strings are attracted to objects with a static electric charge. The pith balls can also be charged by touching them to an object with a static electric charge. 

                                                           

Electroscopes are device used to detect the presence of charge and its relative amount. They are usually constructed with a metal plate or sphere at the top of a metal post with a metal rod hanging from the bottom of the post.

                                                             

These two are charged with differing charges making them very reactive to differing electrical energy and charges that come near to them. This can be caused by the movement of the electrons within the instrument which cause the lighter materials in the instrument to move towards or away a grounded rod that is brought close to it. These instruments will react differently but can be easily understood. We experimented with this in class by grounding several rods with alternating charges and touching and moving the rod around the instruments to see how they react. This can be used to discover the charge of the object by checking how the instruments react, if they are opposite to the object then balls will be attracted to each other and move towards each other, while if they are similar to each other they will be pushed away from each other. In turn an electroscope will move when an electrically charged and grounded object moves near it and will actually stay in an elevated position due to the electrons being transferred to the electroscope through the contact. 

These two instruments are effective at serving as an effective way to test objects in their own way, pith balls can show whether an object has a positive or negative charge, while a electroscope can show the strength of the charge by how it stays up when charged. Thus these instruments are very useful when testing for and find unknown charges.

Lab 6: Energy part one

Lab 6: Energy part 1

To experiment with work and how it affects the energy, velocity, and movement of an object. To do this we set up a friction less track with a slider and weights and began alternating the height and placement of the slider on the track. We would then change the amount of force we exerted on the cart and monitor how fast it traveled a see how that affected the work done. We recorded this information into logger pro, here is an example of the difference between a forceful shove and actually fighting the weights to let the cart fall slower.

The data was partially conclusive with our initial prediction, that more force would move the track faster, but this did not vastly change the integral, averaging on a few 10ths of a joule where a joule is equal to Mass*Newton’s like we had thought it would. 

To expand on this we set the track up as a ramp to test out and see if height or displacement would have any effect on the integral. We varied our height by about 20cm by first testing the slider from 70 cm to 190, and then from 90cm to 190cm. our results are below, and served to concur with our prediction.

We then elevated to track and increased the incline of the ramp and used the same two distance markers.  The heights were different at the same points along the ramp at 90 cm (8.8 cm vs. 10.2 cm).  We compared the integrals and found that height does matter= .3243J vs .2074J for the first trial at a lower incline, as shown here.

These experiments show us that height matters when it comes to work being done.  Potential energy is higher when the incline is higher.  Varying force seems to not affect the work when the distance (displacement) is the same.  This all ties into work done in order to change energy in a system.

Possible issues.

One of the greatest issues we had with the experiment was ensuring that the track stopped smoothly. With such a short track we were forced to abandon several graphs due to this problem as the tracks would flip backwards and disrupt the information, making the graph useless and corrupting the integral measurement. 

Lab 5: Circular motion

Lab 5: Circular motion 

For lab 5 we were asked to find the mass of an object spinning in a circular motion. In order to properly test this we used the DMV Player program Motion in a circle.

To first calculate the mass we needed to find the object velocity.  We set the graph to 30 FPS and monitored the simulation to see how long the graph would take to send the object in a complete circle. We calculated it to take 724 frames to complete its rotation, thus meaning it took 24 seconds to complete its circle. 

The simulation then provided us with the force of the movement up in the top center. We were then able to calculate the velocity of the object by using the rotation motion equation, v=2piR/time, or plugging the numbers into it v=2pi60/3.016, giving us a velocity of 1.25 centimeters. 

We are then able to calculate the acceleration using velocity/radius to get an acceleration of 2.6 MPS. We were then able to plug this into the traditional force formula, F=MA, or in this case 1.15=m*2.6, which we can divide our acceleration into the force for 1.15/2.6=M, or .44Kg of mass for the object.

Errors

Possible errors that could change our results were rounding errors, improper conversions between centimeters and meters.