At the top of it path or anywhere else the Earth's gravity accelerates the ball downward. Regardless what the horizontal mothion is (disregarding air resistance), there are no accelerations after the kick. A ball kicked straight up to the same height will hit the ground at the same time as a ball kicked at 45 degrees.
Acceleration
The combination of a horizontal axis and a vertical axis is called a Cartesian coordinate system, or in short, a graph.
On the horizontal axis you would probably plot the time. On the vertical axis you could plot displacement, velocity or acceleration.
Constant speed ... zero acceleration.
Vertical is up and horizontal is across
If the object is thrown upwards, the vertical acceleration is negative and the horizontal acceleration is zero.
Vertical means up or down, horizontal means left or right (or forward or backwards, but without changing the altitude).
Horizontal . . . acceleration is zero, speed is constant Vertical . . . acceleration is 'G' downward, speed constantly increases downward
That combination is called "projectile motion". In the absence of air resistance, its shape is always a parabola.
Acceleration
The combination of a horizontal axis and a vertical axis is called a Cartesian coordinate system, or in short, a graph.
On the horizontal axis you would probably plot the time. On the vertical axis you could plot displacement, velocity or acceleration.
The bullet fired from a gun has greater horizontal acceleration. For vertical acceleration, they are both the same.
-- The only horizontal force on a thrown ball is the force of air resistance, so the horizontal acceleration is very small, and the horizontal speed stays almost constant. -- The vertical force on a thrown ball is the force of gravity, so the ball accelerates straight down at the acceleration of gravity. -- The result of unequal horizontal and vertical components of acceleration is a curved path.
You need to know about gravity, forces, velocity, acceleration, and vector.
Constant speed ... zero acceleration.
Vertical is up and horizontal is across