# Physics

posted by
**Katrina**
.

when we do convertions, do we have follow the rules for rounding?

is it 118.5cm=1.19m, or 118.5cm=1.18m?

It depends upon how many significant figures (sf) you are allowed, whether you are doing converSions or calculating some other problem. By definition, there are 100.000000000 cm in 1.00000000000 meter; therefore, 118.5 cm = 1.185 m. You have 4 sf in 118.5 and you are allowed to have 4 in the answer.

the precision of the stopwatch is 0.01second, if the question ask us to provide the answer to the nearest 0.1second,so...

12.65seconds=12.6 or 12.7seconds?

Some people do rounding differently when the last number is a 5. I follow the rule to "round to the even number." Therefore, I would round to 12.6 since 6 is the even number. If it were 12.75, I would round to 12.8 (the nearest even number). I hope this helps.