question_answer

Find the power of an electric motor, if it lifts 200 kgf of water in 5 minutes, from a well of 120m depth.

Answer:

Given, weight of water, \[W=mg=200\,\,kgf\] \[=200\times 9.8N(\because 1\,\,kgf=9.8\,N)\] \[=1960\,\,N\] \[t=5\,\,\min =5\times 60s=300\,s\] \[h=120mP=?\] We know, \[P=\frac{mgh}{t}=\frac{1960\times 120}{300}=784\,W\]