Relative to a fixed origin \(O\), the position vector \(\mathbf{r}\) m at time \(t\) s of a particle \(P\), of mass 0.4 kg, is given by
$$\mathbf{r} = e^{2t}\mathbf{i} + \sin(2t)\mathbf{j} + \cos(2t)\mathbf{k}.$$
- Show that the velocity vector \(\mathbf{v}\) and the position vector \(\mathbf{r}\) are never perpendicular to each other. [6]
- Given that the speed of \(P\) at time \(t\) is \(v\) ms\(^{-1}\), show that
$$v^2 = 4e^{4t} + 4.$$ [2]
- Find the kinetic energy of \(P\) at time \(t\). [1]
- Calculate the work done by the force acting on \(P\) in the interval \(0 < t < 1\). [2]
- Determine an expression for the rate at which the force acting on \(P\) is working at time \(t\). [2]