Experimental part

1. Fix the end of the cord in the first position (l = 50 cm). Make the pendulum vibrate (the amplitude of vibration must not be more than the ball diameter). Determine time of 50 oscillations by the stop-watch three times and calculate the period T using the average value of the time.

2. Determine the free fall acceleration g.

3. Calculate an error.

4. Investigate relation between the period T and the length l. Put the end of the cord in the second position (l = 150 cm). Calculate period of oscillations in the same way and compare with T.

5. Increase the amplitude of oscillations twice. Test independence of the period on the amplitude of oscillations (small amplitude and big amplitude).

6. Make conclusions.