In above figure $\left(a\right)$ the man walks $2 m$ carrying a mass of $15 kg$ on his hands. In figure $\left(b\right),$ he walks the same distance pulling the rope behind him. The rope goes over a pulley and mass of $15 kg$ hangs at its other end. In which case is the work done greater?

$\left(a\right)$ Work done by the man against gravity is zero. Because displacement of block is perpendicular to the force applied $\left(N\right)$ by him on the block.
$\left(b\right)$ Work has to be done against gravity ; $W=Ts=mg\times 2=2mg J.$. In addition to this, work is to be done against friction while mov-
ing a distance of $2m$ .Thus the work done in case $\left(b\right)$ is greater than in case $\left(a\right)$.