The problem statement, all variables and given/known data Consider a rigid body with an inertia tensor I =[30, 0, 0; 0, 40, 0; 0, 0, 20] N m s^2 and angular velocity w=10j+10k rad/s. Determine the moment of inertia about an axis parallel to w and find the rotational kinetic energy. The attempt at a solution I'm not sure if the fact that this is the principal moment of inertia matters. Also, I thought this had something to do with the parallel axis theorem, but neither mass nor any distances are given. Any help would be appreciated.