Answer
See the graphs below.
Work Step by Step
a) When the acceleration $\vec a$ at point 2 points up, the particle is speeding up, and hence $\vec v_2$ is greater than $\vec v_1$. See the motion diagram below.
b) When the acceleration $\vec a$ at point 2 points down, the particle is slowing down, and hence $\vec v_2$ is smaller than $\vec v_1$. See the motion diagram below.
