Quote Originally Posted by shinta|hikari View Post
That means Kal's body will not change shape (that means not getting hurt right? Because I believe if I get hit by something that cannot even change the shape of my skin, it won't really hurt?). Like I said, the force will act on him, and he will fly off, but he won't get hurt. Their fists on the other hand, should be the same hardness as the rest of their body. Even with "less" force, it should damage them much more.

In addition, the amount of force exerted by their fists already far exceed what little extra weight the steel beam can provide. Think of it in relative terms. The weight of the steel beam to the aliens is like the weight of a (heavy) pillow to humans.
Not really, the shockwave from an explosion can completely kill you, even though you'd show no external damage, and since the kinetic energy increases with the square of the speed, an object doubling its speed has four times as much kinetic energy, thus swinging the beam with as much force as zod can, the beam generates much more force than he could with a punch.

Even if the beam desintergrated on impact (your pillow analogy), the resulting force will still hurt; like smashing a bottle on someone's much harder skull.