# How to find maximum velocity

I stack a question about projectile question.

The question was

A projectile is being launched from ground level with no air resistance. You want to avoid having it enter a temperature inversion layer in the atmosphere a height $h$ above the ground (a) what us the maximum launch speed you could give this projectile if you shot it straight up ? Express your answer in terms of $h$ and $g$.(b)Suppose the launcher available shoots projectiles at twice the maximum launch speed you found in part (a). At what maximum angle above the horizontal should you launch the projectile ?

I could solve the (a) part. How did was following (a) using the following formula to drive $V$

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