back to the superpowers

Going back to some of the posts I made before with questions on how powers work, let's pick a few more power questions. Oh, and feel free to make suggestions of other powers for me to pick apart in comments.

I know this is technically not a power, but Captain America's shield has always been a bit of a sticking point for me. The alloy that it is made of (sometimes a Vibranium-Adamantium alloy, sometimes different) is basically amazing at absorbing impacts. This allows Cap to use it to stop bullets or even blows from Thor/Hulk level characters with minimal to no force transferred back to him. In essence, the shield nullifies the blow and stops the entire force. Given that, how in the world does the shield bounce when Cap throws it? If the Vibranium in the shield "absobs kinetic impact" (http://en.wikipedia.org/wiki/Captain_America%27s_shield) then wouldn't the shield also absorb and negate the kinetic impact of the shield itself striking an object in flight? Or perhaps it is a special characteristic of the shape of the shield, impact on the rounded front is nullified but impact on the edges is not. Either way, doesn't make a whole lot of sense to me...

Over to DC for a minute, Animal Man's power is a little odd. His body normally does not change in any noticable way, but he can focus and gain a bird's ability to fly (without wings) or a fish's ability to breathe underwater (no gills). So by channeling the strength of a gorilla and punching someone should break his fist and arm because he still has the physiology of a human. In New 52 he has been shown more as taking on forms of the animals he is channeling, but he still flies with no wings. I like Beast Boy better because he actually becomes the animal that he is channeling power from, that makes a lot more sense.