Surface energy is scanned across bound gamma and checked area. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Surface energy reuses a bound gamma source
The energy ledger is allowed to use gamma only by citing the checked line-force source. Area is the second independent input.
E=γA=3N/m⋅8m2=24J
Changing gamma changes surface energy
Area is fixed in these three rows. The energy column changes only because the cited gamma source changes.
γ2N/m3N/m4N/mA8m28m28m2E16J24J32J
Changing area also changes surface energy
Now the gamma source is fixed. The three area rows make the second input-output relationship visible.