1. The problem statement, all variables and given/known data 2. Relevant equations Famous Five equations for uniform accelerated motion 3. The attempt at a solution To be honest, I have absolutely no idea where to start. The only thing that I notice is that at the point where you're given the velocity vector (when the projectile is 10m above the ground) it makes an angle of 45 degrees, which means that both vx and vy are equal. I don't really know where to go from there.