1. A force F = (2.80 N)i + (6.80 N)j + (7.05 N)k acts on a 2.00 kg mobile object that moves from an initial position of di = (3.05 m)i - (2.00 m)j + (5.00 m)k to a final position of df = -(5.00 m)i + (4.05 m)j + (7.00 m)k in 4.00 s. 2. Relevant equations W = Fd 3. The attempt at a solution I thought I could do the pythagorean theorem for the Force... square root (2.8^2 + 6.8^2 + 7.05^2), that would give the magnitude of the force. Then I did the same thing, the magnitude of df - magnitude of di. Then, (magnitude F) * (magnitude df - magnitude di) = W But that is incorrect. I am using Web assign online and the answer I get from the previous method does not work. Can anyone explain?