Let the vortex$/$sink flow simulate a tornado $($as in Lecture $30).$ Suppose that the circulation

about the tornado is $8000$ m $!/$s and that the pressure at r $=40$m is $2000$ Pa less than the

far$-$field air pressure $(101$ kPa$).$ Assuming inviscid flow at sea$-$level density $(=1\mathrm{.}2$ kg$/$m$3),$

find $($a$)$ the appropriate sink strength $,($b$)$ the pressure at r$=10$m$.(20$ points$)$