We know that if force F acting on an object to displace it through a distance S in one direction, than the work done W on the body by the force is given by :
Work done = Force `xx` Displacement
`W = F xx S`
Where,
`F = 7N`
S = 8 m
Therefore, work done, `W = 7 xx 8`
= 56 Nm
= 56 J.