Explanation:
The Work [tex]W[/tex] done by a Force [tex]F[/tex] refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:
[tex]W=(F)(d)[/tex] (1)
In this case both (the force and the distance in the path) are parallel (this means they are in the same direction), so the work [tex]W[/tex] performed is the product of the force exerted to push the box [tex]F=45N[/tex] by the distance traveled [tex]d=12m[/tex].
Hence:
[tex]W=(45N)(12m)[/tex] (2)
[tex]W=540Nm=540J[/tex]