determine the number of significant figures 640 cm

Question

trancenova · Answer

It has two significant figures, http://en.wikipedia.org/wiki/Significant_figures

anonymous · Answer

The trailing zero counts as a significant figure. It has 3 significant figures.

aroub · Answer

3

anonymous · Answer

2.

aroub · Answer

arrr!!!

aroub · Answer

how come?!

anonymous · Answer

Um because i guess the zero to the right isn't counted =/

aroub · Answer

no zeros to the left don't count..

trancenova · Answer

I think it depends on what system you're using.. according to Wikipedia it would only be 2 unless it had a decimal point (eg. 620. )
which would indicate that the number is measured to 620 exactly. However 620 itself could just mean 6.2*10^2, which is 2 sig figures. I've probably just confused everyone more though... including myself

aroub · Answer

LOL!

anonymous · Answer

In the format it's listed, i.e. measured cm at 640 it is 3 SF. If they listed it as 6.4m it would be 2 SF.

anonymous · Answer

This is fresh in my mind. Had it beat into my head in Chem class. Even got dinged for dropping SFs ;)

trancenova · Answer

Lol, okay will believe you Osirisis, though do you know why it is 3?

anonymous · Answer

Because by have the last 0 making it 640 you are removing variance for that digit. You're making clear that it doesn't vary between 636cm and 644cm which would all round to 6.4m. The extra 0 puts certainty to that digit. Instead it pushes the possible variance to 639.6cm to 640.4cm. A tighter tolerance for any variance if you will.

anonymous · Answer

*having

aroub · Answer

thanks osirisis!! :D