(2) If the lever is unbalanced in the horizontal position, the right end inclines downwards and the center of gravity moves to the left, so the hook code moves to the left.

(3) Different physical quantities can't be added directly. If only one set of data is used to draw a conclusion, it will be too accidental. It is necessary to obtain multiple sets of experimental data to summarize the physical laws.

So the answer: (1)

(2) Move the hook code to the left;

(3) The conclusion is incorrect, because different physical quantities cannot be added directly, and it is too accidental to draw a conclusion with only one set of data.