Here the x axis is along the ground, R is the range, and h is the maximum altitude. where \mathbf{v}_{0} is the initial velocity of the cannonball, called the muzzle velocity. Typicall...Here the x axis is along the ground, R is the range, and h is the maximum altitude. where \mathbf{v}_{0} is the initial velocity of the cannonball, called the muzzle velocity. Typically in real life you will not know the cartesian components of the velocity vector ( v_{x 0} and v_{y 0} ); instead you are more likely to know the magnitude of the muzzle velocity v_{0} and the launch angle \theta.
