<P> This expression assumes that the rod is an infinitely thin (but rigid) wire . This is a special case of the thin rectangular plate with axis of rotation at the center of the plate, with w = L and h = 0 . </P> <Tr> <Td> Rod of length L and mass m, rotating about one end . <P> This expression assumes that the rod is an infinitely thin (but rigid) wire . This is also a special case of the thin rectangular plate with axis of rotation at the end of the plate, with h = L and w = 0 . </P> </Td> <Td> </Td> <Td> I e n d = m L 2 3 (\ displaystyle I_ (\ mathrm (end)) = (\ frac (mL ^ (2)) (3)) \, \!) </Td> </Tr> <P> This expression assumes that the rod is an infinitely thin (but rigid) wire . This is also a special case of the thin rectangular plate with axis of rotation at the end of the plate, with h = L and w = 0 . </P> <Tr> <Td> Thin circular hoop of radius r and mass m . <P> This is a special case of a torus for a = 0 (see below), as well as of a thick - walled cylindrical tube with open ends, with r = r and h = 0 . </P> </Td> <Td> </Td> <Td> I z = m r 2 (\ displaystyle I_ (z) = mr ^ (2) \!) I x = I y = m r 2 2 (\ displaystyle I_ (x) = I_ (y) = (\ frac (mr ^ (2)) (2)) \, \!) </Td> </Tr>

Moment of inertia of a disc about its axis