A particle moves along a straight line from a fixed point O. Its displacement, s metre, at t seconds after passing O is given by [math]s=2t^3-24t^2+90t[/math]. Calculate[br]
(a) the distance, in m, of the particle from the fixed point O when t=8,
(b) its velocity, in ms[sup]-1[/sup], when t=1,
(c) its acceleration, in ms[sup]-2[/sup], when t=3,
(d) the values of t, in seconds, when the particle stops momentarily.