[Suicide Junkie]

The ripping process eats up a lot of energy in the breaking of bonds and a bit in the final acceleration of the two halves of the rope.

In the ship example, presuming the block and shots all stick together, you end up with a block with two bullets in it, and two ships both moving away from the block.

The thing you're not getting is that you don't "apply kinetic energy" to anything. You exert forces. The force may be countered by friction or an opposing force.
You can waste energy all you want, you'll just get hot and sweaty without getting the result you wanted.