ABSTRACT
W = F • u ||F|| ||u|| cos θ ,
where F is a constant force u is the displacement θ is the angle between the vectors F and u satisfying 0 ≤ θ ≤ π .
Algebraically, for two vectors r1, r2 in R3,
r1 • r2 = ⎡
⎣ x1 y1 z1
⎤
⎦ • ⎡
⎣ x2 y2 z2
⎤
⎦ = x1x2 + y1y2 + z1z2.
