Flux
Engineering term for flow rate through surfaces
Refers to the amount and rate at which a liquid (or gas) enters or leaves a surface. Mostly used in engineering courses, but it is also seen in vector calculus.
Find the flux of the vector function F(x,y,z)=xyi+y^2*arctan(y*z)j-exp(2*x*z) over the unit sphere z=p^2.