At the top of a projectile's motion, the total acceleration vector depends on two factors: gravity and air resistance.

1. Gravity (Vertical Component):

   • The acceleration due to gravity ($g$) always acts downward (towards the ground) with a magnitude of approximately 9.8 m/s².

2. Air Resistance (Horizontal and Vertical Components):

   • If air resistance is not ignored, it will act in the direction opposite to the ball's velocity. Since the ball has no vertical velocity at the top of its motion, the vertical air resistance is zero at that point.
   • However, the ball still has a horizontal velocity, so air resistance will act horizontally to the left (opposite to the ball’s motion).

Conclusion:

The total acceleration vector at the top of the motion will have:

• A downward component due to gravity.
• A leftward component due to air resistance.

Thus, the total acceleration vector will point down and slightly to the left.

Would you like more details or have any questions?

Here are some relative questions to deepen your understanding:

1. How does air resistance affect the motion of a projectile?
2. What is the role of gravity in projectile motion?
3. How do you calculate the horizontal and vertical components of acceleration?
4. How does air resistance change the shape of a projectile's trajectory?
5. In what situations can air resistance be ignored in projectile motion problems?

Tip: When air resistance is considered, the object’s motion becomes more complex, often requiring numerical methods for precise solutions.