5 A particle P of mass 4 kilograms moves in such a way that its position vector at time \(t\) seconds is r metres, where
\(\mathbf { r } = 3 t \mathbf { i } + 2 \mathrm { e } ^ { - 3 t } \mathbf { j }\).
- Find the initial kinetic energy of P .
- Find the time when the acceleration of P is 2 metres per second squared.
Section B (93 marks)