Solve this:

16. A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. (a) Compare : (i) the work, and (ii) power developed by them. (b) How much work each does ? Take density of water = 10³ kg $m^{-3}$ and g = 9.8 N k$g^{-1}$.

                                                                                                             Ans. (a) (i) work 1 : 1, (ii) power 2 : 3,                                                                                                                          (b) work done by each = 3.92 kJ