what is the name of the force that keeps things afloat
Buoyancy For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a non-inertial reference frame, which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction. In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body.[3]
Irresistible force paradox The irresistible force paradox, also called the unstoppable force paradox, shield and spear paradox, is a classic paradox formulated as "What happens when an unstoppable force meets an immovable object?" This paradox is much like the omnipotence paradox, which is a simple demonstration that challenges omnipotence. The immovable object and the irresistible force are both implicitly assumed to be indestructible, or else the question would have a trivial resolution. Furthermore, it is assumed that they are two separate entities