Answer
(a) No such moment.
(b) The point of maximal height.
Work Step by Step
(a) No, there is no such point. We know that during the projectile motion, the velocity has two components. The vertical component is tangential to the fight while the horizontal component is always to the right. Thus, velocity is not parallel to the acceleration in the given scenario.
(b) When the ball reaches its maximum height, then the ball's velocity is perpendicular to its acceleration.
