$\"\"$

Height of the cylindrical water tank is $\"\"$ .

Radius of the layer is $\"\"$ .

The water weighs $\"\"$ .

Volume of the disk is $\"\"$ .

Distance the disk of the water is moved $\"\"$ .

Weight of disk of the water is $\"\"$ .

Therefore, the weight of the layer is $\"\"$ .

$\"\"$

Calculate the work done in pumping a full tank of water up to the ground level :

$\"\"$

Apply integration :

$\"\"$

The work done in pumping a full tank of water up to the ground level is $\"\"$ .