A particle moves with position function s = t4 - 4t3 - 8t2 + 25t, t2 0 (a) At what time does the particle have a velocity of 25 m/s? (Enter your answers as a comma-separated list.) t = (b) At what time is the acceleration 0? (Round your answer to two decimal places.) t = 3.76 What is the significance of this? At this time, the acceleration changes from positive to negative and the velocity attains its minimum value. At this time, the acceleration changes from negative to positive and the velocity attains its minimum value. O At this time, the acceleration changes from positive to negative and the velocity attains its maximum value. At this time, the acceleration changes from positive to negative and the velocity attains a value of zero. O At this time, the acceleration changes from negative to positive and the velocity attains its maximum value.