Why doesn't Newton's Third Law prevent work from being done?

Question

I apply a force on an object. The object applies an equal and opposite force on me. I realize the forces are on two distinct bodies and do not cancel each other out. Accordingly, the work done by me and the work done by the object are being applied on and by different objects.

However, the work done by me on the object is $F\times{}d$ and the work done by the object on me is the same. If a body does $x$ joules of work, and has $x$ joules of work done on it, there should be no change in the total energy of the object. The work done by it and on it is equal. How can this be possible? Has the object not gained kinetic energy?

Not a duplicate of Newton's Third Law and Work Done on a Body. My question is about the perspective of a single box rather than of the whole system.

Answer 1

You are absolutely right. You do work on the object, and the object does an equal amount of (negative) work on you. It cancels out and this system of you-and-object doesn't gain any energy and hence doesn't move as a whole.

But if you only look at the object and only draw a free-body diagram for the object, then there is no force from the object on anything. There is only a force on the object and thus only work done on the object. This work is unbalanced, and manifests as kinetic energy and thus motion of the object.