### Q.5(d):- In Fig. 6.13(i) the man walks 2 m carrying a mass of 15 kg on his hands. In Fig. 6.13(ii), he walks the same distance pulling the rope behind him. The rope goes over a pulley, and a mass of 15 kg hangs at its other end. In which case is the work done greater?

**Answer:-**

__Work done in fig 6.13 (i)__

Mass, *m* = 15 kg

Displacement, *s* = 2 m

Work done, W = *Fs Cos*θ

Where, θ = Angle between force and displacement

= *mgs Cos*θ = 15 × 2 × 9.8 *Cos* 90^{0}

= 0

__Work done in fig 6.13 (ii)__

Mass, *m* = 15 kg

Displacement, *s* = 2 m

Here, the direction of the force applied on the rope and the direction of the displacement of the rope are same.

Therefore, the angle between them, *θ* = 0°

Since cos 0° = 1

Work done, *W* = *Fs* cos*θ* = *m*g*s*

= 15 × 9.8 × 2 = 294 J

Hence, more work is done in the *Fig.* 6.13 (ii).