PERIODIC MOTION:
PENDULUM
PROCEDURE
The set up for this experiment is simple. The pendulum is suspended by a string and the period is measured by allowing it to oscillate past a photogate timer. The timer is interfaced so that it measures the elapsed time for one full swing, or the Period.
2. Set up the pendulum with a 1.5 meter length. Enter this value in cell B11 on the Worksheet. The string should be tied with a slip knot ( the same kind you tie your shoes with). Place a 50 g mass on the mass holder, giving the bob a total mass of 100 g.
3. With the pendulum perfectly still at equilibrium, carefully place the photogate at the equilibrium point with its jaws up, but so that it will touch the pendulum as it swings.
4. Carefully pull the pendulum back and release it cleanly to check that it will swing without hitting the photogate. You should not pull it back more than about 10 cm from equilibrium. Practice releasing it cleanly.
5. Make sure that the photogate cable is attached to the DataLogger box, and that the unit is switched on.
6. Open the Pendulum Timer link. A Period vs. Time graph will appear.
7. Pull back the pendulum and release it so it oscillates without hitting the photogate. Click the Collect button on the computer.
8. Allow the pendulum to swing for about 200 seconds, then hit Stop on the timer window. Select the ANALYZE...Statistics menu item. Find the Mean Period in the floating box on the Period vs. Time plot, and record it in cell B12 on the Worksheet.
9. Select the Table Window and record the very first period value and the very last period value in cells B13:B14 on the Worksheet.
10. Repeat the same procedure for three more pendulum lengths: 1.25 m, 1.00 m and 0.75 m. Record the data in cells C11:E14 on the Worksheet.