Question

pls solve 16th question

Answer 1

Since they both lift the same amount of water, up the same distance, their work work done are the same. So the ratio of work done by the boy and his father are 1:1.

Let's say that each of them does W amount of work. Power is Work per unit Time.

Power of boy = P1 = W/3
Power of father = P2 = W/2

Hence the ratio of Power developed by them are :-
(P1/P2) = 2/3 = 2:3

Work done is the product of force and the displacement brought about, in the direction of force.

Hence

W = F.S

Where F is the force and S is the displacement.

W = (Mg).S

1 Litre = 10^(-3) m^3
Hence Mass of water = M = V×d = 20×10^(-3)×10^3 = 20 Kg.

Hence F = Mg = 20×9.8 = 196 N

Thus the work done is

W = F.S
W = 196×20
W = 3920 J

W = 3.92 kJ