@article{santos_oliveira_nelson_2012,  title={Impedance of rigid bodies in one-dimensional elastic collisions},  volume={34},  ISSN={1806-1117},  url={https://doi.org/10.1590/S1806-11172012000100005},  DOI={10.1590/S1806-11172012000100005},  number={1},  journal={Revista Brasileira de Ensino de Física},  publisher={Sociedade Brasileira de Física - SBF},  author={Santos, Janilo and Oliveira, Bruna P.W. de and Nelson, Osman Rosso},  year={2012},  month={Jan},  pages={1305} }