Answer
The momentum is the same for both.
$$(1 kg)(2 \frac{m}{s}) = (2 kg)(1 \frac{m}{s} )$$
The faster, less massive ball has the greater KE.
$$\frac{1}{2}(1 kg)(2 \frac{m}{s})^{2} > \frac{1}{2}(2 kg)(1 \frac{m}{s} )^{2}$$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.