1 point of Adaptive Force provides 0.6 bonus AD or 1 AP.
If the attack damage and the ability power of the unit are equal, the stat granted depends on the champion.
In most cases, the League of Legends Wiki omits adaptive force in favour of displaying the amount of AD or AP granted.
Sources of adaptive force bonuses
A similar effect can be found on:
Adaptive Damage: Deals either physical or magic damage depending on your bonus statistics, defaulting based on the origin of the effect.
Adaptive damage does not take into account your target's resistances or your own penetration stats.
Sources of adaptive damage