# The vertical component of surface tensions in wetting

To find the contact angle made by a droplet on a flat surface at equilibrium, we take the sum of all surface tensions at the boundary of the droplet to be equal to zero (Wikipedia link). Projecting surface tensions in the horizontal direction gives Young's equation: $$\gamma_{SG}=\gamma_{SL}+\gamma_{LG}\cos(\theta)$$.

My problem is with the vertical component of these tensions: Taking only surface tensions into account, clearly the vertical component is different from zero ($$\gamma_{LG}$$ is the only tension with a vertical component and there's nothing to counter it), so the boundary point cannot be at equilibrium. What is missing?