Answer
Please see the work below.
Work Step by Step
We can find the displacement in the x direction as
$x=vt$
We plug in the known values to obtain:
$x=(4.5)(18)=81m$
Similarly, the displacement in the y direction is
$y=(\frac{1}{2})at^2$
We plug in the known values to obtain:
$81=(\frac{1}{2})(a)(18)^2$
$a=0.5\frac{m}{s^2}$
