#find the moment of inertia of a rotating body around the y axis, with the density of 1
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I_y=\int_{A}\rho \cdot x^2 dA
where A is the shaded area
and dA=dxdy
Now we must find the boundaries of x and y
So when y\in[0,2], the variable x varies from x=0 to the line that passes through the points (2,0) and (4,4) which is y=2x-4 after solving for x, the upper bound is (y+4)/2
When y \in [2,4] the variable x varies from line that passes through the points (0,2) and (4,4) to the line y=2x-4 which implies that x \in [(y-2)/2;(y+4)/2]
Iy=\int_{0}^{2}\int_{0}^{(y+4)/2}1 \cdot x^2 dxdy+\int_{2}^{4}\int_{(y-2)/2}^{(y+4)/2}1 \cdot x^2 dxdy
Solve both integrals
Post marked as solved by @wise pond.
Use .unsolved if this was a mistake.
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