Aparticle moves according to the law of motion s(t) = t^{3}-8t^{2}+2t, t\ge 0, where t is measured in seconds and s in feet. a.) find the velocity at time t. b.) what is the velocity after 3 seconds?c.) when is the particle at rest? enter your answer as a comma separated list. enter none if the particle is never at rest. at t_1= and t_2= with t_1