Question

a) Suppose you are using a timer that reads time in seconds to two decimal places. The timer is started by an apparatus that has negligible uncertainty, but you have to stop it by pressing a button when you see a certain event take place. The timer reads 4.37 seconds. Write this time interval (including its uncertainty) to reflect your 0.2 sec reaction time. 4-0 1x b) Same as a), but you have to start the timer as well as stop it. Suppose yo speed of light. The speed you found was 186,200 miles per second. a) If you write your result as "186,200 mi/ someone reading it think it has? Fous C H) b) Suppose your experiment is very accurate, and you believe both zeroes in "186,200 mi/sec" are significant. Show this by two different techniques. u have done an experiment in which you took data that enabled you to calculate the see", how many significant figures wll 86,200 uith elertriral cirits and your instrument allows you to

Answer 1

a)

reading of timer = 4.37

uncertainty = $\pm$0.2

so 4.37 $\pm$0.2

b)

uncertainty is involved in both starting and stopping the timer , so total uncertainty is given as

uncertainty = $\pm$(0.2 + 0.2) = $\pm$ 0.4

so 4.37 $\pm$0.4

a)

186200 miles/sec

this number has 4 significant figures.