pumping out a liquid - work

A tank in the shape of an inverted right circular cone has height http://webwork2.asu.edu/webwork2_fil...fc95b6a081.png meters and radius http://webwork2.asu.edu/webwork2_fil...0ef0978d41.png meters. It is filled with http://webwork2.asu.edu/webwork2_fil...47b840b231.png meters of hot chocolate.

Find the work required to empty the tank by pumping the hot chocolate over the top of the tank. Note: the density of hot chocolate is http://webwork2.asu.edu/webwork2_fil...61b7b03a91.png

$\displaystyle

A = \pi r^2

$

$\displaystyle

V = \pi r^2 \triangle{x}

$

$\displaystyle

\frac{r}{h} = \frac{13}{8}

\frac {r}{8-x} = \frac{13}{8} r=\frac{13}{8}(8-x)

$

$\displaystyle

V = \pi (\frac{13}{8})^2 (8-x)^2 \triangle x

$

$\displaystyle

F = ma = V*p*g

$

$\displaystyle

F = \pi (\frac{13}{8})^2 (8-x)^2 (1550)(9.8) \triangle x

$

$\displaystyle

W = \int^8_1 [\pi (\frac{169}{64}) (8-x)^2 (1550)(9.8)] dx

$

$\displaystyle

W = \frac{2567110\pi}{64} \int^8_1 (8-x)^2 dx

$

$\displaystyle

W = 14407454.03 J

$

Can anyone see where i went wrong?

Thanks for any help :)