Work done is given by product of force and displacement due to that force
So here we will have

here we know that


Now work done is given as


so it will do 16 J work to move the box
True !! Hope I helped you out a bit!
The same amount of work being done over a long period of time!
The mass affects the kinetic energy because the more the mass the more energy is given to the object and the speed<span> affects by making it go faster and longer, so whenever speed goes up so does energy.</span>