A football is kicked from a position on the ground that is 40.0 m from the base of the goal. If the ball strikes the top cross bar which is 3.00 m above the ground, at what two angles could the ball have been kicked? (Assume the ground is horizontal.
3=vi*sinTheta*t-1/2 g t^2 and
40=vi*cosTheta*t
so you have three unknowns: t, vi,and theta. Cant be solved.