And I promise not to start with the really hard problems this time! How’re the problems going? You can do this!! If you are talking angular projectiles, the resultant velocity is actually made up of two things – horizontal velocity and vertical velocity. The horizontal velocity never changes, the vertical velocity has a different direction going up and coming down, but it has the same speed at equal levels. Now, if you’re talking horizontal projectiles, the resultant velocity is the same as the horizontal velocity of the gun, because that’s the only kind of initial velocity it has!
Draw a picture, write what you know, resolve the resultant velocity into vertical and horizontal, find formulas that fit (because it will hardly ever be solved with just one) and go for it!! Capisce? 🙂 Oh, by the way – don’t forget the conceptual stuff!