Why will a cradle run forever in vacuum?

At least, that's how it would work in an "ideal" Newton's cradle, which is to say, one in an environment where only energy, momentum and gravity are acting on the balls, all the collisions are perfectly elastic, and the construction of the cradle is perfect. In that situation, the balls would continue to swing forever.

plz mark me as brainliest if this helped :)

the answer is trees if i'm not mistaken

the answer to your question is slate