Answer
$2.94 \times 10^{6} \ J$
Work Step by Step
The force of one layer is equal to:
$\ Force= \ Mass \times \ gravity = 9.8 \times (1000) \times 32 \Delta y \ N=313600 \Delta y \ N$
Therefore, the work done against can be computed as:
$ W=\int_{2.5}^{5} 313600 y \ dy \\=313600 [\dfrac{y^2}{2}]_{2.5}^{5} \\ =156800 [y^2]_{2.5}^{5} $
By using a calculator, the required result is:
$W \approx 2.94 \times 10^{6} \ J$
