# Measurement Activity

# Time of Fall Experiment

View **MIT Physics 8.01 Lecture 1** starting at 22:10 (available on ITunes U and MIT Open CourseWare) and then discuss the following questions. For your convenience, Prof. Lewin's analysis and measurements are reproduced below.

Prof. Lewin's dimensional analysis:

Prof: Lewin's height measurements:

Prof: Lewin's time-of-fall prediction and measured times:

Prof. Lewin's calculated results:

## Questions:

- Prof. Lewin originally assumed that the time of fall of an object depended on what quantities?

- How did Prof. Lewin conclude that the time of fall of an object did
*not* depend on its mass?

- Prof. Lewin used dimensional analysis to conclude that the time of fall of an object was proportional to what?

- How did Prof. Lewin arrive at an uncertainty of 0.006 m for his calculation of h
_{1}/h_{2}? What would be a shortcut way to do this? Do you get the same result with the shortcut?

- How did Prof. Lewin justify an uncertainty of 0.002 s for the time of fall of the object?

- How did Prof. Lewin arrive at an uncertainty of 0.002 s for the
*theoretical* ratio of t_{1}/t_{2}?

- How did Prof. Lewin arrive at an uncertainty of 0.008 s for the
*measured* ratio of t_{1}/t_{2}?

- Do Prof. Lewin's experimental results confirm or cast doubt on his hypothesis. Explain your answer clearly.

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*last update March 27, 2008 by JL Stanbrough*