If we neglect air resistance, the only force acting on the ball during its trajectory is the force due to gravity. At the highest point of its trajectory, the ball momentarily stops moving vertically and changes direction. Therefore, its velocity at the top of the trajectory is zero.
However, the ball still experiences acceleration due to gravity, which remains constant throughout its motion. Near the Earth's surface, the acceleration due to gravity is approximately 9.8 m/s², directed downward.
So, at the top of its trajectory: Velocity: 0 m/s (since the ball momentarily stops moving vertically) Acceleration: -9.8 m/s² (directed downward)