The motion of a particle along a straight line is described by equation x = 8 + 12t - t3 where, x is in meter and t in second. The retardation of the particle when its velocity becomes zero, is

Given, x = 8 + 12t - t3We know that, v = dxdt and a = dvdtSo,                   v = 12 - 3t2and                   t = 2s,                         v = 0and                    a = -12 ms-2So, retardation of the particle = 12 ms-2.