Halliday, Resnick & Walker — Kinetic Energy and Work: Problem 51

A force \(\vec{F} = (3.00\,\hat{i} + 7.00\,\hat{j} + 7.00\,\hat{k})\text{ N}\) acts on a \(2.00\text{ kg}\) mobile object that moves from an initial position \(\vec{d}_i = (3.00\,\hat{i} - 2.00\,\hat{j} + 5.00\,\hat{k})\text{ m}\) to a final position \(\vec{d}_f = (-5.00\,\hat{i} + 4.00\,\hat{j} + 7.00\,\hat{k})\text{ m}\) in \(4.00\text{ s}\). Find (a) the work done on the object by the force in the \(4.00\text{ s}\) interval, (b) the average power due to the force during that interval, and (c) the angle between vectors \(\vec{d}_i\) and \(\vec{d}_f\).