If work is done by a body against a force,is the work considered positive or negative?

At time $t=0$,a particle starts moving along the $x$-axis. If its kinetic energy increases uniformly with time $t$,the net force acting on it must be proportional to

$A$ man pushes a wall and fails to displace it. He does:

$A$ man carries a bucket of weight $60 \ N$ and walks $7 \ m$ in the horizontal direction,then climbs $5 \ m$ in the vertical direction. What is the work done by the man in $J$?

You lift a heavy book from the floor of the room and keep it in the bookshelf having a height of $2 \, m$. In this process,you take $5 \, s$. The work done by you will depend upon:

$A$ heavy box of $40\, kg$ is pushed along $20\, m$ by two coolies over a railway platform whose coefficient of friction with the box is $0.4$. The work done by the two coolies is: .................. $J$ (Take $g = 10\, m/s^2$)