Answer
Not Conservative
Work Step by Step
For a vector field to be Conservative, $\dfrac{\partial f}{\partial y}=\dfrac{\partial g}{\partial x}$
We have: $f(x,y)=x^3-xy$ and $g(x,y)=\dfrac{x^2}{2}+y$
Thus, $\dfrac{\partial f}{\partial y}=-x$ and $\dfrac{\partial g}{\partial x}=2x$
Therefore, a vector field $F$ is Not Conservative.