A particle moves along the x-axis. At time t=0 the particle passes through the origin with speed 8ms-1 in the positive x- direction. The acceleration of the particle at  time t seconds, t is greater than or equal to 0, is (4t^3-12t)ms-2 in the positive x-direction. Find: a) the velocity of the particle at time t seconds  b) the displacement of the particle from the origine at time t seconds  c) the values of t at which the particle is instantaneously at rest