# Parabolas and projectiles

Given $2$ points, $A$ and $B$, if I am in $A$ and I have an inclination angle $c$, with how many velocity do I need to shoot a projectile to hit $B$ ? My problem is, how do I setup this data in an equation so that I can solve it with a program?

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Strength is an elusive concept. Do you actually mean velocity? Then it would be independent of mass. If you mean force, one would need to know how long the force was applied. – André Nicolas Nov 22 '12 at 2:21
Thanks,it´s edited. Let´s work with the velocity to eliminate m. How can I work with this variables? – chubakueno Nov 22 '12 at 2:27

Let $A$ be the origin and $B$ be $(x,y)$. The angle of projecting is $c$. The parabolic trajectory is given by the formula below $$y = x \tan(c) - \dfrac{g}{2u^2 \cos^2(c)}x^2$$ This gives us $$u^2 = \dfrac{gx^2}{2 \cos^2(c) (y-x \tan(c))}$$ Hence the unique velocity is $$u = \left \vert \dfrac{x}{\cos(c)} \right \vert \sqrt{\dfrac{g}{2(y-x \tan(c))}}$$

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thank you, this solved my problem in a nutshell – chubakueno Nov 22 '12 at 2:46