Velocity and acceleration of a ball thrown upwards

When a ball is thrown vertically upward, it first goes through an upward motion, reaches the maximum height, and then comes vertically downwards.

For this entire route, if we ignore air resistance then the only force acting on the ball is gravity. This force pulls the ball vertically downwards.

Velocity of a ball thrown upwards

Velocity During the Upward motion (before reaching maximum height)

Hence, during the upward motion, the ball moves with retardation as gravity force acts in the opposite direction of the motion. Hence, its velocity falls following this equation V=U-gt.
Here, U is the initial velocity with which it is thrown vertically upward, and V is its velocity after a duration of t during its upward movement. g is the acceleration due to gravity.

Velocity at the maximum height of the vertical motion

Velocity at the maximum height is zero. At this point, the kinetic energy of the ball becomes zero. And its potential energy becomes maximum.

Velocity during the downward motion

During the downward motion, the ball moves with acceleration because gravity now acts in the direction of the motion. Hence, its velocity increases following this equation V=U+gt.
Here, U is the initial velocity of the downward motion, and at the maximum height, it is actually zero. V is its velocity after a duration of t during its downward movement. g is the acceleration due to gravity.

Velocity just before touching the ground or reaching the initial point of throw

Before touching the ground the velocity becomes equal to the initial velocity with which it was thrown vertically upward. At this point, the kinetic energy of the ball becomes maximum. And its potential energy becomes zero.

Acceleration of a ball thrown upwards

The acceleration of a ball thrown upwards remains the same throughout the vertical motion, including the upward and downward motion. This acceleration equals g (acceleration due to gravity).