If I had two pistons of areas $A_1$ and $A_2$ where $A_1 > A_2$, and I pushed them with the same force against one another, would they be in an equillibrium and cancel each other out, or will the piston with area $A_2$ win because it has greater pressure?
The reason why I'm asking is because when we talk about fluids like air or water, we always talk in terms of pressure, and when there's a higher pressure on one side and lower pressure on the other side, fluids go to the lower pressure, but why would that be the case if the forces are the same and the areas are different?
Also, take a nail piercing through a wall. If I applied the same force on a nail, why would surface area matter? If the force applied is the same, how can the wall crack just by deacreasing the surface area of the applied force, if force is defined as a thing that makes the objects it is exerted on accelerate?