The question
Name: ______________________ Date: ____________ Measuring g with a pendulum (10 points)
Data table
Pendulum timing data
A student wants to determine the magnitude of the gravitational field g in the classroom using a small metal bob on a light string hung from a clamp. The student has a meterstick, a stopwatch and a protractor.
The student's data for five lengths are shown. Length ℓ is measured from the pivot to the center of the bob; each bob was released from rest at about 8°.
| Length ℓ (m) | Time for 10 oscillations (s) |
|---|---|
| 0.20 | 9.0 |
| 0.40 | 12.6 |
| 0.60 | 15.6 |
| 0.80 | 17.9 |
| 1.00 | 20.1 |
(a) Describe an experimental procedure the student could use to collect data like these. Include what is measured, with which equipment, and one way to reduce experimental uncertainty. [3 points]
(b) Indicate what quantities could be graphed to yield a straight line whose slope could be used to determine g. Explain how g is found from the slope. [2 points]
(c) On the grid, plot the data points for the quantities you indicated in part (b). Clearly label the axes with quantities and units, use a linear scale, and draw a best-fit line for the data. [3 points]
(d) Calculate an experimental value for g using the best-fit line. [2 points]