How can a mace penetrate armor better than a sword? So, I'm trying to comprehend, just why are weapons like maces are so good at killing opponents through armors (full-plate), that sword edges can't even hope to dent. When I skimmed through google, I couldn't find any physics-based answer, so I ask it here.
 A: The center of weight for maces is pretty much exactly in line with the area of impact. If you strike something with a sword, you are likely to not hit with the center of mass, which means that you will lose kinetic energy that could go to the area of impact, to torque (i.e. the sword "rolls off").
Even if you do manage to hit with the center of gravity, it's a matter of force/Area: A mace will unload its kinetic energy into a very concentrated spot, whereas a sword will unload it over the entire area of the edge.
Also, armor is designed so that swords are deflected; maces will care less about the slope at which they hit their target.
And the last reason I can think of, is that maces of the same weight have a larger inertial torque; so it takes longer to swing a mace, but you will accumulate a higher kinetic energy during the swing.
A: The mace has a greater mass, and hence greater momentum. This means when it collides with the armour/person  there is a greater change in momentum. As $F=\frac{\Delta p}{t}$, this means the force acting on the person will be greater, resulting in more damage. 
Swords use the concept of the force being concentrated on a small area to pierce, but this doesn't work on armour.
