In fig. (i) the man walks 2 m carrying a mass of 15 kg on his hands. In Fig. (ii) , he walks the same distance pulling the rope behind him. The rope goes over a pulley, and a mass of 15 kg hangs as its other end. In which case is the work done greater ?

Explanation

In fig. (A), force is applied on the mass, by the man in vertically upward direction but distance is moved along the horizontal .
`:. theta = 90^(@) , W = FS cos 90^(@) `= zero
In fi.(b) , force is applied along the horizontal and the distance moved is also along the horizontal . Therefore `v = 0^(@)`
W = FS cos v = `mg xx S cos 0^(@)`
`W = 15 xx 9.8 xx 2 xx 1 ` = 294 Joule .
Workdone in `2^(nd)` case is grater .