The function 5(t) describes the motion of a particle along a line. 5(t) = 6r t2 (a) Find the velocity function v(t) of the particle at any time t 2 0. v(t) = (b) Identify the time interval on which the particle is moving in a positive direction. (Enter your answer using interval notation.) (c) Identify the time interval on which the particle is moving in a negative direction. (Enter your answer using interval notation.) (d) Identify the time at which the particle changes direction. Find the point of inection of the graph of the function. (If an answer does not exist, enter DNE.) f(x) = x3 3x2 + 26x 24 (x, y) =