1. The problem statement, all variables and given/known data The two systems are equivalent. If F = 30i - 100j + 40k lb and M' = 40i - 80j + 120k lb*in, determine F' and M. Here's a pic of the problem: http://img214.imageshack.us/img214/339/fc1g.jpg [Broken] 2. Relevant equations M = r x F 3. The attempt at a solution To find M, I started out finding the position vector for System 1 and got r = 6i + 0j +6k, and then did the cross product of that with F = 3i - 100j + 40k, and got M = 600i - 222j - 600k. To find F' for System 2, I took r to be 6i + 4j + 6k. I then set up the cross product box, with the F' row blank, and tried finding F' with the known answer of M' = 40i - 80j + 120k, however it is practically impossible to solve for F' that way and something tells me that's not the right way to try to solve it anyway. Also, something tells me that I didn't solve for M in the first part correctly either.