In physics, the formula for the displacement of a projectile in motion is:
This can be translated to the form :
This equation produces a parabola which describes the height of the projectile above the ground and the time the projectile is in the air.
Note: gravity on Earth is

How long does a ball stay in the air if it is thrown at 10m/s from 1.2m off the ground?

How fast would a ball need to be thrown to stay in the air for 5 seconds? Assume the thrower's arm is 1.2m off the ground.

How is the time in the air affected by the initial throw speed? gravity? the height of the person? What would happen if there was no gravity?

How does the gradient change over time? What is the gradient at the maximum height? What does the gradient describe about the motion of the ball? When is the ball moving the fastest?