5 At time \(t\) seconds, where \(t \geqslant 0\), a particle P of mass 2 kg is moving on a smooth horizontal surface. The particle moves under the action of a constant horizontal force of ( \(- 2 \mathbf { i } + 6 \mathbf { j }\) ) N and a variable horizontal force of \(( 2 \cos 2 t \mathbf { i } + 4 \sin t \mathbf { j } ) \mathrm { N }\). The acceleration of P at time t seconds is \(\mathrm { am } \mathrm { S } ^ { - 2 }\).

1. Find a in terms of t. The particle P is at rest when \(\mathrm { t } = 0\).
2. Determine the speed of P at the instant when \(\mathrm { t } = 2\). Answer all the questions.
   Section B (91 marks)