A rock is thrown directly upward from the edge of the roof of a building that is $\mathrm{}\mathrm{}56\mathrm{.}3$ meters tall. The rock misses the building on its way down, and is observed 

to strike the ground $4\mathrm{.}00$ seconds after being thrown. Take the acceleration due to gravity to have magnitude $9\mathrm{.}80$ m$/$s$\mathrm{²}$ and neglect any effects of air resistance. With what speed was the rock thrown?