We'll apply the formula of the moment of
inertia:
I = (pi*sigma/2)(a^4 -
b^4)
Knowing, from enunciation, the mass of the circular
ring is:
I = (M/2)(a^2 +
b^2)
We'll insert the given
values:
I = 0.191(0.110^2 +
0.015^2)/2
I = 1.177*10^-3
Kg*m^2
The absolute error in a is delta
a.
The fractional error in a is delta
a/a.
The fractional error in a^2 is 2delta
a/a.
The absolute error in a^2 is 2adelta a and the
absolute error in ab2 is 2bdelta b.
The absolute error in
a^2+b^2:
a^2+b^2 = sqrt[4a^2(delta a)^2 + 4b^2(delta
b)^2]
a^2+b^2 = 1.23*10^-2
m^2
From this value results a fractional
error of 1.8%.
The fractional error in M is
:
M = (0.003/0.191)
M =
1.6%
I = sqrt(1.8^2 + 1.6^2)
%
I =
2.4%
I = 1.177*10^-3 Kg*m^2
+/- 2.4%
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