Four graphs of acceleration versus time are shown. Assume that each grid cell has width 1 s1 s and height 1 m/s21 m/s2. (Actual numeric values are not required for ranking as long as all axes are scaled the same.) a) Select the choice that ranks the graphs in order from the most negative change in velocity to the most positive. (b) Suppose the initial velocity is v0=−5 m/sv0=-5 m/s. Rank the graphs from the smallest to the greatest final speed. vd