Answer:
The work done shall be 14715 Joules
Explanation:
The work done by a force 'F' in a displacement 'dy' is given by
[tex]W=m(y)g\times dy[/tex]
At any position 'y' the weight shall be sum of weft of water and weight of string
[tex]\therefore m(y)=m_{water}(y)+m_{string}(y)\\\\m(y)=30(1-\frac{y}{10})+0.9y[/tex]
Thus applying values we get
[tex]W=\int m(y)g\times dy\\\\W=\int_{0}^{10}(30(1-\frac{y}{10}+0.9y)\times g)dy\\\\Solving\\W=294.3\int_{0}^{10}(1-\frac{y}{10}+0.9y)dy\\\\W=14715J[/tex]