Name: Charles Xu,
Partner: Anthony
Date: 09/07/2016
Statment:
It was a experiment that use excel and logger pro to find the g (acceleration) for free falling body.
Theory:
Using the electromagnet to spark dots on the paper tape, then use excel to find the velocity vs time graph. The slope of the graph is the g value we want to find.
Summary:
We use electromagnet and the sparker thing to record dots on a piece of paper tape during free falling. Then we measure the distance between the dots and input into excel. We input time interval as 1/60 s. Then we use excel to calculate ∆x, mid interval time (the time for the middle of each 1/60 interval) and mid internal speed (∆x/mid-intercal time) for us. Then we select the data columns of Mid-interval time and Mid-interval speed to create a chart. Also, we use data columns of Time and distance to create a time vs distance graph.
The set up of electromagnet
Measuring the distance between dots using meter stick.
The excel with data we collected and the graphs we plot.
Then we use datas from other groups to calculate the uncertainty of the experiment by using excel again.
First, we calculate the average value of 8 groups. Then, we deviated from the mean and square the deviation. Next, we took the average of 8 numbers we have from last step and square root it to get the uncertainty value.
Datas of 8 groups
The excel for finding uncertainty
Conclusion
We find the number of 955 for the result, which is within the range of +- 25 uncertainty. I think it is a successful experiment. Some groups have more precise result than us. I think there is uncertainty and human error during the measurement. There are many little dots on the paper tape, we might measure the wrong dot or not precise enough that cause the errors. Also, we didn't consider air residence in this experiment. it could be a factor of error too.
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