Practical 2 Measurement of g
Introduction
This practical uses the pasco freefall apparatus to measure the time taken for a ball to fall a measured distance. Students are instructed to repeat measurements and find uncertainties as in the two introductory practicals 0 and 00.
Assessment
This practical is not used as part of the assessment because too much information is given in the instructions, however it is marked according to the criteria so that students get some feedback on the following criteria so students understand how the assessment will be done.
Feedback is given on the following criteria
DCP
Students should fill in a table incuding units and uncertainties. The table should have the same decimal points in a column, these should be reasonable. I also expect sudents to explain how they estimated the uncertainties. Students should calculate t² in the table and plot the graph correctly including custom error bars, labels and units. They should also plot a best fit line plus steepestand least steep lines.
CE
Students should calculate g from the gradient of the graph, this should be compared to the book value. Students should also give an estimate of the uncertainty in g from the steepest and least steep best fit to .They should also make some comments about the graph relating it to the apparatus, it is not good enough to simply say "air restance was a source of error" unless the graph shows that it might have been. Any possible improvements to the method should be described.
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