1. The problem statement, all variables and given/known data 2. Relevant equations N/A 3. The attempt at a solution I have 2 (basic) questions about this system: 1) The question says that ωAB = ωABk, I understand that bold indicates vectors whilst the plain text indicates a magnitude so ωAB (magnitude) multiplied by k (direction vector) gives you the vector ωAB. However, why do we multiply the magnitude by k (to yield the vector ωAB) as opposed to multiplying by i or j? I'm trying to picture this in my head but struggling to. 2) Am I correct in saying that ωAB = ωBA? That is, does the order of the letters in the subscript of the vector matter? Does this matter for magnitudes (e.g. ωAB = ωBA), vectors^ or both/neither?