a tank is formed by revolving the curve y=x^2 ; 0<=x<=4 ; around y-axis

if filled with water with weight 10000 N/m^3

find work needed to empty the tank by pumping it to the top ?

the problem is that i dont have the height to set the integral

is it right if i use the radius as 4?

this way ill get V=PI r^2 dy

F=10000*V

W=(?) *F

integral limits ==??

any help or hints pls :)