Determine the principal axes and principal moments of inertia of
(a) the rectangular plate in question 2, for rotations about a corner,
(b) the brick in question 3, for rotations about its centre of mass,
(c) a uniform cube of mass 
with edges of length 
,
for rotations
about the midpoint of one of its edges.
[In some of these cases you should be able to find the directions of the principal axes without diagonalising any matrices.]
[Hints can be found here, but do not follow this link until you have attempted the question on your own.]