The ball was thrown down from a height of 1.5 m relative to the floor. With what speed was the ball thrown

The ball was thrown down from a height of 1.5 m relative to the floor. With what speed was the ball thrown if, after hitting the floor, it jumped to a height of 5.5 m? Neglect energy losses during movement and impact

h1 = 1.5 m.
g = 10 m / s2.
h2 = 5.5 m.
V2 = 0m / s.
V1 -?
To solve this problem, we will use the law of conservation of total mechanical energy. The total mechanical energy of the ball does not change, but passes from one type to another. The total mechanical energy is the sum of the ball’s kinetic and potential energy.
m * g * h1 + m * V1 ^ 2/2 = m * g * h2 + m * V2 ^ 2/2.
Since the height h2 = 5.5 m is the maximum, then at this height the speed of the ball is V2 = 0 m / s.
m * g * h1 + m * V1 ^ 2/2 = m * g * h2.
V1 = √ (2 * g * (h2 – h1)).
V1 = √ (2 * 10 m / s2 * (5.5 m – 1.5 m)) = 8.9 m / s.
Answer: the ball was thrown vertically downward at a speed of V1 = 8.9 m / s.