The velocity-time graph for a particle \(P\) travelling in a straight line is shown.

(a) Find

(i) the acceleration of \(P\) at \(t=5\),

(ii) the distance travelled by \(P\) in the first 10 seconds.

A second particle \(Q\) moves with velocity \(v=3\sin2t-1\), where \(t\) is measured in seconds and \(v\) in metres per second.

(b) Find

(i) the speed of \(Q\) when \(t=\dfrac{7\pi}{12}\),

(ii) the first positive value of \(t\) for which \(Q\) has zero acceleration.