Question

Time intervals measured with a stopwatch typically have an uncertainty of about 0.2 s , due to human reaction time at the start and stop moments.What is the percent uncertainty of a handtimed measurement of 6 s ? What is the percent uncertainty of a handtimed measurement of 50
s? What is the percent uncertainty of a handtimed measurement of 4
min? i forgot how to figure this out

Answer 1

the uncertainty is fixed at 0.2 s

as the timed interval becomes longer
... the fixed uncertainty becomes a smaller percent

(0.2 s / 6 s) * 100%

(0.2 s / 50 s) * 100%

[0.2 s / (4 * 60 s)] * 100%