1 A particle P has position vector \(\mathbf { r } \mathrm { m }\) at time \(t\) s given by \(\mathbf { r } = \left( t ^ { 3 } - 3 t ^ { 2 } \right) \mathbf { i } - \left( 4 t ^ { 2 } + 1 \right) \mathbf { j }\) for \(t \geq 0\).
Find the magnitude of the acceleration of P when \(t = 2\).