The formula for finding the final height (displacement) of a ball thrown vertically upwards with constant acceleration is as follows:
Δy = v₀y * t + (1/2) * a * t²
Where: Δy is the final height or displacement v₀y is the initial vertical velocity t is the time of flight a is the acceleration (in this case, the acceleration due to gravity, which is approximately -9.8 m/s²)
Since the ball is thrown vertically upwards, the initial vertical velocity (v₀y) will be positive. However, the acceleration due to gravity acts in the opposite direction, so it will be negative in this case.
If you know the initial vertical velocity and the time of flight, you can use this formula to calculate the final height or displacement of the ball when it reaches its highest point before falling back down.