For each of the following stream functions, with units of \(\mathrm{m}^{2} / \mathrm{s}\), determine the magnitude and the angle the velocity vector makes with the \(x\) axis at \(x=1 \mathrm{~m}, y=2 \mathrm{~m}\). Locate any stagnation points in the flow field.

(a) \(\psi=x y\)

(b) \(\psi=-2 x^{2}+y\)