Question

Say we have a diameter of 22.1 mm with uncertainty +-0.1mm
Now we have to calculate the percentage uncertainty in area.

Answer 1

My question is basically what happens to the uncertainty when you divide the diamater by 2 to get the radius?

Answer 2

what is the figure of the object first?

Answer 3

A circle

Answer 4

basically this is what I would do, I hope you understand

First I would find he area of the circle
let area=x
then I would say
y=x-0.1
z=x+0.1
then add the uncertainties... y+z
after adding them up, divide them by the area and multiply by 100...and you have the percentage uncertainty! :)

Answer 5

What I am asking is that when you divide diameter 22.1mm by 2, if anything happens to the uncertainty?

Answer 6

are you asking if uncertainty will double or something like that?

Answer 7

no it would be constant

Answer 8

i think

Answer 9

So if it's a constant then nothing happens to it?

Answer 10

Nothing happens to the percentage uncertainty

Answer 11

the diameter will have the same uncertainty as the full circle
but you can try it practically
find are of a circle then find it with half the measurement and see

Answer 12

Ok I see. Thanks for your help!