Sig figs introductory physics course

AI Thread Summary
The discussion centers on the correct representation of significant figures in a physics problem involving velocity. The problem states the velocity as 2/3 m/s, and there is confusion over whether to express it as 0.66 or 0.6 when rounding to two significant figures. It is clarified that the correct answer is 0.67, as the zeros to the left of significant digits do not count as significant figures. The consensus emphasizes that 0.6 is not an accurate representation of the value when considering significant figures properly. The conversation highlights the importance of understanding how to express numbers in scientific notation and the rules governing significant figures.
Teachme
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I was reading a problem my brother was assigned in his introductory physics course. The problem specifically asks to give the velocity from viewing a graph. The velocity is 2/3 m/s and it asked to give it in two significant figures. So I thought it would be .66, however the online site he was doing it on said this was incorrect and said the answer was 0.6. I do not agree with this since I was always led to believe the 0 is not a significant figure. Am I incorrect to say that the answer is .66 for two sig figs? I think they just made a mistake. Or am I missing something?

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I meant to say 0 is not significant figure when to the left of other numbers.
 
Teachme said:
I meant to say 0 is not significant figure when to the left of other numbers.
You are right, the zeros "to the left " indicate the magnitude. Writing the number in normal form, 2/3 = 0.66= 6.6 x 10-1 with two significant figures.
Imagine you have to give 2/30 with two significant figures. It is not 0.0!

ehild
 
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I would call it 0.67.
 
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Well, of course!

ehild
 
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