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Lucy Yeats
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Homework Statement
A mass distribution in the positive x region of the xy-plane and in the shape of a semicircle of radius a, centred on the origin, has mass per unit area k. Find, using plane polar coordinates, its moments of inertia about the x and y axes.
Homework Equations
The Attempt at a Solution
I know that I=∫r^2.dm
dm=k.dA=k.r.dr.dθ in polar coordinates.
So I=k∫dθ∫r^3.dr
But I'm not sure about the limits, or how to differentiate between the moments of inertia about the x and y axes.
Any help would be brilliant.