The article claims the only force acting on the hammer while it is in the air is gravity. Who says? Clearly Thor's Hammer has characteristics very different from a static solid object. For example: It can't be picked up by anybody other than Thor, not even the Hulk. Yet it is not so heavy as to crush through the floor of a building when left sitting on the floor. And Thor can walk on things like ordinary soil while carrying it and not leave unusually deep footprints. Something unusual clearly is happening here.
There has to be some active technology going on inside the hammer. But we don't really get any clear explanation of how the hammer achieves what it achieves. So we don't really know the only force acting is gravity. We do not even know that the force of gravity is constant on the hammer. That might be how it avoids getting picked up.
The article's focus is more on the real physics and not the mythical properties of the hammer. The techniques used to find the center of mass from recorded video are interesting and show what you can or can't infer from video in general.
The conclusion that the hammer violates these laws provide some insight into how realworld science is done and how discoveries are made. If the hammer was a realworld object then this would lead to investigation of the test results, corroboration of results by other teams and finally to a new theory of how it works.
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