2. A particle \(P\) of mass 3 kg moves such that at time \(t\) seconds its position vector, \(\mathbf { r }\) metres, relative to a fixed origin, \(O\), is given by
$$\mathbf { r } = \left( t ^ { 2 } - 3 t \right) \mathbf { i } + \frac { 1 } { 6 } t ^ { 3 } \mathbf { j }$$
where \(\mathbf { i }\) and \(\mathbf { j }\) are perpendicular horizontal unit vectors.
- Find the velocity of \(P\) when \(t = 0\).
- Find the kinetic energy lost by \(P\) in the interval \(0 \leq t \leq 2\).