question_answer

A fire hose is uncoiled by pulling the end of the hose horizontally at a uniform speed of 2.2 m/s. If the linear density of the hose is \[0.2\text{ }kg{{m}^{-1}},\] find the work done in uncoiling the 20 m hose.

Answer:

Mass of hose uncoiled \[=20\times 0.2=4\,\,kg\] \[K.E.\frac{1}{2}m{{v}^{2}}=\frac{1}{2}\times 4\times {{2.2}^{2}}=9.68J\] \[\therefore \]Work done\[=9.68\,J.\]