Answer
$8.0 \times 10^5\ N $
Work Step by Step
We need to use the formula such as: $F=\int_0^h \rho g F(y) w(y) \ dy$.
Plug in the above formula the given values to obtain:
$F= \int_0^{50} (150+2y) (80) \ dy\\=\int_0^{50} (12,000+160y) \ dy \\=[12000 y+80 y^2]_0^{50} \\=8.0 \times 10^5\ N $
