A rock is thrown from the roof of a building with a velocity v_0 at an angle of alpha_0 from the horizontal. The building has height h. You can ignore air resistance. Calculate the magnitude of the velocity of the rock just before it strikes the ground. 2. Relevant equations V=V_0 + at X=V_0t + 1/2at^2 3. The attempt at a solution v_0(sin(alpha_0))-2(v_0) The catch is that when i put the answer into the system, it told me that v_o and alpha_0 are not part of the answer. Any help is appreciated.