See Error, Uncertainty and Graphs: Propagation of Errors .
Is the absolute error given valid for the radius ? What is the power n in equation (1.8) in your case ? Is the error given divided by the diameter valid for the relative error of the radius ? Is the relative error of r^3 the same as the relative error of[(4/3 pi) r^3] (see equation (1.3)) ?
14 comments:
Help!
I need help too! I don't understand how to calculate the error of the sphere, can anyone help me with this.
I too am also having trouble. Delta V is what Im trying to find. so I have DeltaV/V = |n|*DeltaR/R
My Diameter was .17, with accuracy of .005m. My radius will be .085m.
Volume calculated is .002572m^3
DeltaV/.002572 = |3| * (.0025^(.05/2)) / (.085^(.17/2))
Is that equation set up correctly?
Having trouble with this also.
My radius would be .07m. Do I calculate the volume by (4/3)*pie*(.07^3)
And then how to I go about the error.
My diameter is .2m so the radius is .1m. I plug .1m into the formula (4/3)pi(.1)^3 to get the volume of the sphere and it comes out incorrect. I've been having this problem with volume+area. I have no idea how I could possibly have done anything wrong. I mean I also tried different sig figs and rounding up and down but I can't come across the right answer.
DeltaS/S= [n]*DeltaA/A
what I got was, 0.13m (diameter)+/- 0.005m( as error)
To calculate the absolute error,
first, you should get DeltaS/S.
DeltaS/S= 3*(0.005m/0.13m)=0.115
And then use the equetion 1.4
DeltaX=deltaX/X*X
So, in my case, 0.115*.00115=.000133
Good Luck guys!!
what is .00115? why did you put that into equation 1.4?
please someone help. i have no clue what to do.. someone plz just give their example.
I am having trouble with this as well.
The error that they are giving you is for the diameter. You have to divide that by 2 to get the error for the radius because the radius is half of the diameter. Then use equation 1.8 and you'll get it right.
This is how you calculate the error:
Using equation 1.8:
Delta S/S = n * Delta A/A
...which really means...
Error in Volume/Volume = exponent * Accuracy/Diameter
With a Diameter=.15m, Accuracy of .005m and a volume of .0018m^3 it looks like...
Delta S/.0018 = 3 * .005/.15
Delta S (aka Error in volume) = .00018 m^3
This took me like 18 tries to figure out. If everyone's having this much trouble with just the first lab, I'm kinda scared for the rest of them.
My numbers are .12m (Diameter) and .005 (error. Here is what I've done to find the error:
Relative Error=3*(.005/.12)=.125
Absolute Error=.125*.000905m^3(vol)= .000131 m^3
However when I put this into the answer box it keeps telling me I'm wrong. What am I doing wrong in my calculation??? Anyone know?
Try to put it in Sci Notation
Can anyone answer this question? I finished the quiz pressed grade it gave me the grade...Then I went back into the quiz again to review stuff and it started me on another NEW Quiz. Since my first was graded has it been submitted or do I have to do another whole quiz again to get credit???
Thanks
Re all: see Erica 9/10 3:26 pm:
Erica's comment:
Using equation 1.8:
Delta S/S = n * Delta A/A
...which really means...
Error in Volume/Volume = exponent * Accuracy/Diameter
(here Erica uses equation (1.3) delta(aX)/(aX) = (DeltaX/X) with a = (4/3 pi)
(here Erica uses (1.3( with a = 2 from d=2r))
With a Diameter=.15m, Accuracy of .005m and a volume of .0018m^3 it looks like...
Delta S/.0018 = 3 * .005/.15
(here Erica uses equation (1.4) to convert relative to absolute error)
Delta S (aka Error in volume) = .00018 m^3
Post a Comment