Please only answer part 2 of this screenshot. I am not sure how to plot this velocity field. I am using Matlab but any advice would be helpful.

Consider the velocity fields of two vortex flows: u=r/a^andu=(r/a)^, where ^ is an azimuthal unit vector, a is a typical length scale of the vortex, say the "vortex core radius", and represents the strength of the vortex. Analyze these two vortices as follows: I. What are the units of ? What does mean physically? (Hint: what bappens when r=a? ). 2. Plot a sample velocity field for each vortex using software/webtools of your choice