Chapter 2 - Force Vectors - Section 2.8 - Force Vector Directed Along a Line - Problems - Page 67: 98

$F = [-34.3i + 22.9j -68.6k]\ lb$

$r_{AB} = (-3i + 2j + 6k)$ $r_{CB} = \dfrac{1}{2}_{AB} = (-1.5i + j + 3k)$ Then: $r_{CO} = r_{BO} + r_{CB} = -6k -1.5i +j + 3k = -1.5i +k -3k$ $r_{CO}' = 3.5\ lb$ Calculating: $F = 80\dfrac{r_{CO}}{r_{CO}'} = 80\dfrac{-1.5i +k -3k}{3.5} = [−34.3i+22.9j−68.6k]\ lb$