A particle is moving in a straight line such that \(t\) seconds after passing a fixed point \(O\) its displacement, \(s\) m, is given by

\(s=3\sin2t+4\cos2t-4.\)

(i) Find expressions for the velocity and acceleration of the particle at time \(t\).

(ii) Find the first time when the particle is instantaneously at rest.

(iii) Find the acceleration of the particle at the time found in part (ii).