Atwood's Device Lab
Name: Kyle Collins
Lab Partner: Parker Fairchild
Date: 2 October 2014
Purpose: The intent of this lab is to investigate the Atwood's device in order to obtain a better of dynamics in physics.
Theory: Reverend George Atwood created his eponymous device in 1784 in order to publish the paper "A Treatise on the Rectilinear Motion and Rotation of Bodies, with a Description of Original Experiments Relative to the Subject". The Atwood's Device is a basic physics device used to demonstrate basic principles of dynamics and acceleration, consisting of a pulley, a string, a system of masses suspended from it, and in this experiment, a photogate.
Lab Partner: Parker Fairchild
Date: 2 October 2014
Purpose: The intent of this lab is to investigate the Atwood's device in order to obtain a better of dynamics in physics.
Theory: Reverend George Atwood created his eponymous device in 1784 in order to publish the paper "A Treatise on the Rectilinear Motion and Rotation of Bodies, with a Description of Original Experiments Relative to the Subject". The Atwood's Device is a basic physics device used to demonstrate basic principles of dynamics and acceleration, consisting of a pulley, a string, a system of masses suspended from it, and in this experiment, a photogate.
In order to find acceleration in the system, an equation needs to be derived. The work is shown below. W represents weight, T represents tension, m represents mass, a represents acceleration, g represents the force due to gravity, and 1 and 2 distinguish the mass hangars.
Experimental Technique: The device was set up so that there was always a 5g difference in the mass of the hangers. Each hanger was massed, and the number was recorded. Next, the acceleration was measured using DataStudio and the quadratic equation. The coefficient of a from the quadratic was multiplied by two to give acceleration. Lastly, the acceleration was calculated using the derived equation; a percent difference equation showed the difference between the two values.
Data and Analysis:
Data and Analysis:
The measured accelerations consistently proved to be significantly smaller than the ones that were measured, often with significant percent differences. The lowest data set is a trial run to see whether or not increasing the difference would result in smaller percent differences. However, the acceleration increased in all runs. This is because net force is equal to mass times acceleration, and if mass decreases, acceleration must increase in order to maintain a constant net force.
Conclusion: The percent differences in this experiment were much higher than anticipated. This is likely because the string used was thick and had a considerable amount of friction and mass. Since the device works under the assumption that the string is both frictionless and massless, this probably skewed the results greatly. The difference between the mass hangers was only 5g, and thus the acceleration was barely enough to overcome friction. To attempt to work around this, another run was completed where the difference was 50g, and this resolved the issue of the extremely high percent differences.
Conclusion: The percent differences in this experiment were much higher than anticipated. This is likely because the string used was thick and had a considerable amount of friction and mass. Since the device works under the assumption that the string is both frictionless and massless, this probably skewed the results greatly. The difference between the mass hangers was only 5g, and thus the acceleration was barely enough to overcome friction. To attempt to work around this, another run was completed where the difference was 50g, and this resolved the issue of the extremely high percent differences.
References:
http://physics.kenyon.edu/EarlyApparatus/Mechanics/Atwoods_Machine/Atwoods_Machine.html
http://www.aplusphysics.com/courses/honors/dynamics/Atwood.html
http://physics.kenyon.edu/EarlyApparatus/Mechanics/Atwoods_Machine/Atwoods_Machine.html
http://www.aplusphysics.com/courses/honors/dynamics/Atwood.html