Physics Explanation

The work done by a force is calculated as the dot product of the force vector (F) and the displacement vector (S). Since the body is constrained to move only along the z-axis, only the z-component of the force contributes to the work done. W = F·S = (-1)(0) + (2)(0) + (3)(4) = 12 Joules. The x and y components of the force do no work since there's no displacement in those directions.