1 answer
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The maximum height is where V = 0.
The acceleration rate is -g, in either direction.
The initial speed is the same as the final speed (because of conservation of energy.)
The time it takes to decelerate from initial speed V to 0 is V/g.
The time it takes to accelerate from 0 to -V is also V/g
This works whether the projectile goes straight up or not. V represents the vertical velocity component.