Answer:
* First fight the reaction time of the person, which is approximately 1/10 s, remember that the stopwatch does not stop alone
* Problems to synchronize when starting to measure the oscillation and end point of the oscilloscope, this error needs a good control system to be decreased.
*Effect of friction with air
Explanation:
In the measurements of the oscillatory movement in general, the most difficult magnitude of the measurement is the period, by reasoning
* First fight the reaction time of the person, which is approximately 1/10 s, remember that the stopwatch does not stop alone
* Problems to synchronize when starting to measure the oscillation and end point of the oscilloscope, this error needs a good control system to be decreased.
* Effect of friction with air