question_answer

Calculate the work done in lifting 20 litres of water through a vertical height of 6m (assume \[\text{g}=\text{1}0\text{m}/{{\text{s}}^{\text{2}}}\], density of water\[=\text{1 g}/\text{cc}\])

Answer:

Volume \[(v)=20\,\,litres=20\times {{10}^{-3}}{{m}^{3}}\] \[(\because 1\,\,litre={{10}^{-3}}m)\] \[g=10\,\,m/s\] \[h=6m\] \[d=1000\,kg/{{m}^{3}}\] \[(\because \,1g/cc=1000\,kg/{{m}^{3}})\] \[W=?\] \[W=mgh=vdgh\]                 \[=20\times {{10}^{-3}}\times 1000\times 10\times 6\]                 \[=1200\,J\]