Board Thread:Speculation House/@comment-14640999-20140724024429/@comment-25091485-20140811133138

Just jumping in to provide some of my opinions:

The Snake Ren was facing did not fully wind up to strike and did not use its full body mass to strike Ren, in fact it was pulling back and immediately reversed direction to strike Ren. (probably less momentum)

Im quite certain that while the snake is heavy, the truck is probably heavier or about the same weight at least. But the point is that the truck had a lot more acceleration and momentum than the snake, thus giving it a lot more force.

In the case of Penny stopping the truck, she first had to absorb the force of impact and not be compressed by that immense force, before using her bracing on the ground to act as pivot for the truck (she dosen't actually lift it) and thus causing the shattering of the road as the force is channeled through her and into the ground. Im pretty sure that you have to be pretty strong to actually stop a speeding metal truck without even pushed back a little. Secondly, even if someone could do that, the force travelling through them probably would cause some serious damage. (But Penny being a robot and all...)

An analogy for this could probably be something like catching a ball, just a really really big fast metal ball.