x(t) = v0xt, (2)
where v0x denotes the initial velocity in the
x-direction. As equation (2) shows, the projectile
is not accelerated in the x-direction and thus will
not change its velocity according to Newton’s
first law. Note that both equations can be treated
independently, but what we eventually observe is
the superposition of both types of motion, E r(t) =
(x(t), y(t)).