# Significant Figure Help:

• Aug 23rd 2008, 05:37 PM
qbkr21
Significant Figure Help:
• Aug 23rd 2008, 06:07 PM
Jhevon
Quote:

Originally Posted by qbkr21

the rule is, you can only be as certain as the least accurate info you were given. so the number of significant figures your answer should have is the least number of significant figures of any info you were given. in this case, that's 2, from the 8.3 ft
• Aug 23rd 2008, 06:12 PM
qbkr21
RE:
So then what would my answer be 60? Also how does my work look is it correct. I'm still learning.

Thanks,
qbk21
• Aug 23rd 2008, 06:31 PM
Jhevon
Quote:

Originally Posted by qbkr21
So then what would my answer be 60? Also how does my work look is it correct. I'm still learning.

Thanks,
qbk21

it would be 61, but i haven't checked your work yet...
• Aug 23rd 2008, 06:38 PM
qbkr21
Quote:

Originally Posted by Jhevon
it would be 61, but i haven't checked your work yet...

If you could double check I sure would appreciate it. Thank you so much.

qbkr21
• Aug 23rd 2008, 06:48 PM
Jhevon
Quote:

Originally Posted by qbkr21
If you could double check I sure would appreciate it. Thank you so much.

qbkr21

your work looks ok to me.

are you sure sig figs are the problem? maybe the program asked for a specific number of decimal places instead, or maybe it is looking for something else even
• Aug 23rd 2008, 06:52 PM
qbkr21
Quote:

Originally Posted by Jhevon
your work looks ok to me.

are you sure sig figs are the problem? maybe the program asked for a specific number of decimal places instead, or maybe it is looking for something else even

Let me ask you one other thing in regards to significant figures...

[1] 320.57 -(3103.5/1.9)

The correct number of significant figures is 2.

Step 1 => (3103.5/1.9) = 1633.42105263

What would be the correct number of figures here?
• Aug 23rd 2008, 06:58 PM
Jhevon
Quote:

Originally Posted by qbkr21
Let me ask you one other thing in regards to significant figures...

[1] 320.57 -(3103.5/1.9)

The correct number of significant figures is 2.

Step 1 => (3103.5/1.9) = 1633.42105263

What would be the correct number of figures here?

it would be 2 as well, which would require you writing in scientific form, that is, $1.6 \times 10^3$

it may also be the convention to write 1600, check your text to see if this is employed
• Aug 23rd 2008, 06:59 PM
qbkr21
Quote:

Originally Posted by Jhevon
it would be 2 as well, which would require you writing in scientific form, that is, $1.6 \times 10^3$

Ok I think I'm getting the picture (Headbang)

Thank You
• Aug 23rd 2008, 07:25 PM
qbkr21
RE:
Just one other thing.

Suppose I wanted to convert

1.50 kg/m3 to g/L

I did and got 1.5 using only 1 significant figure how would I write this?
• Aug 23rd 2008, 07:30 PM
Spec
1.50 $kg/m^3$ is 1.50 $g/L$

1.50 with one significant number is 2, but you don't lose any significant numbers in the conversion from $kg/m^3$ to $g/L$.

• Aug 23rd 2008, 07:49 PM
qbkr21
RE:
I read the article in it's entirety. I'm just still confused.

1) 0.050 L to mL

I converted and found the answer to be 50 ml so I tried writing as 5 x 10^1

The system said it was wrong

2) 8.0 x 10^-8 m to nm

I converted and found the answer to be 80 nm so I tried writing as 8 x 10^1

The system said it was wrong

I'm still stuck.

Thanks,
qbkr21
• Aug 23rd 2008, 08:21 PM
Spec
Maybe the system is expecting such an ambiguous answer? Have you tried entering 50 ml instead of 5.0 x 10^1 ml?

Note the bold text.
• Aug 23rd 2008, 08:46 PM
qbkr21
RE:
Quote:

Originally Posted by Spec
Maybe the system is expecting such an ambiguous answer? Have you tried entering 50 ml instead of 5.0 x 10^1 ml?

Note the bold text.

In subtraction you know how you take the result of the fewest decimal places.

What if you subtract a number that doesn't a decimal place such as

320.57-1600
• Aug 23rd 2008, 08:51 PM
Spec
The problem is that it is a bit ambiguous to write 1600 instead of 16 x 10^2. 1600 can be both 16 x 10^2 and 16.00 x 10^2.

In the first case you're limited to two significant numbers, and in the latter to four.