question_answer

A cylindrical barrel is buried vertically in ground with its opening at the ground level. The area of cross-section of the barrel is\[\text{1 }{{\text{m}}^{\text{2}}}\]. The depth of a barrel is 1.5 m. It is full of water. Find the work done in bailing out the water.

Answer:

Volume of water to be bailed out \[=area\times depth\] \[=1\times 1.5=1.5\,{{m}^{3}}\] Mass of water \[=1.5\times 1000=1500\,kg\] During the bailing out, the water level decreases gradually, so the shift in C.G is to be considered. \[Shift=\frac{depth}{2}=\frac{1.5}{2}=0.75m\] Work done \[=1500\times 9.8\times 0.75=11025J\]