Group+1+(Jimyo's+Team)

Group 1's lab-(Jimyo, Jay, Glenna)
=Abstract= The purpose of the experiment was to study Newton's Second Law of Motion by the use of the Atwood's Machine. We determined the force of friction on the pulley by using two uneven masses through the transfer of paper clips from one side to the other. We observed the motion of the two masses and how their movement would change as the masses changed. Our experimental and calculated acceleration is 13.333 and 9.8 m/s^2 respectively.

=Introduction= The purpose of this lab is to find the value of acceleration due to gravity using the Atwood's machine. The machine has two weights with a pulley balancing each side. The machine must be calibrated for friction on the friction by transferring paperclips until the heavier side will drop down with constant acceleration just by slightly pushing down on the heavier side. From here we measure the time of different masses the fall to the ground. Using the data here we can find a value for acceleration. Our predicted value for acceleration is 13.3333 m/s^2.

=Procedure= Materials needed: Simple Atwood's machine, String, 2 100g weights, paperclips (30), timer.

Preparations:
 * 1) Take a weight and tie it to the string. Do not cut the string yet. Put the weight through the Atwood's machine and drop it to the ground. The other end of the string should be close to the top. This is where the string should be cut off. Tie the other weight to the side of the string that was just cut off.
 * 2) Add 15 paperclips to each side.

Determining force of friction:
 * 1) Transfer on clip at a time from one side to the other until the system moves at a constant speed when given a slight push. Calculate the frictional force on the pulley by subtracting the value. Record the data.

Finding acceleration:
 * 1) With the ascending mass on the floor, release the descending mass, start the timer, and stop the timer when the descending mass reaches the floor.Record the time. Repeat for two more trials. Find the average of these times and record it. Using y = .5at^2 to calculate the acceleration of the system.
 * 2) Transfer 2 more paper clips from the ascending side to the descending side. This lab should maintain the total mass throughout the entire time. Repeat the directions taken in step one.
 * 3) Continue to transfer mass from the ascending side to the descending side for a total of 5 trials.
 * 4) Compute the acceleration of the system using Fnet = ma for each trial. Compare the two values.
 * 5) Using the acceleration of procedure 4, plot a graph of acceleration vs (m - m2) / (m1 + m2) Compute the experimental value for the acceleration due to gravity and compare to the accepted value.

=Data/Graphs=

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=Results & Discussion= Using the graph we get a value of 13.33 m/s^2 as the value of acceleration from gravity compared to the universally accepted 9.8 m/s^2. The value we found was off from the true value due to timing based on sight, humans are prone to not be able to time correctly, especially when timing short intervals is critical for this lab. Other errors include whether the amount of paper clips added to one side was the right amount as a calibration for friction. Paperclips often fell a lot during this experiment and each paperclip are not expected to have the same mass. Each time both sides fell their could be a change in our calibration for friction. These are minor errors and the experimental value is reasonably close to the calculated value.

=Analysis= % Error: 36.05% Error
 * 13.33 - 9.8| / 9.8 * 100%

=Conclusion= The lab works well using Atwood's machine. We were able to find a value for acceleration due to gravity that is close to the actual value with a 36.05% error. Doing this experiment again will require weights that are small but more precise and similar. Paperclips are fine but having precise equipment is key to getting a value close to the calculated value. Same with the pulley by using a lighter pulley. =Questions:= 1. Transferring mass from one side to the other keeps the whole system at a constant mass. It will make calculations easier in general since we do not have to recalculate mass differences and sums for every trial. 2. Differences between the experimental and calculated values are caused by human error of pressing the stop button at the sight or sound of the weight falling on the ground and our ability to count. 3. The tension should be the same because both sides are using the same string. 4. A lighter pulley will give us an easier time with friction being as small as possible. Overall it will give us better results