Considerations on finding the rolling and spinning friction coefficients Florina-Carmen Ciornei, Stelian Alaci, Sorinel-Toderas Siretean, Mariana-Catalina Ciornei, Ioan-Bogdan Dragoi and Vlăduţ-Constantin Lazăr MATEC Web Conf., 184 (2018) 01009 Published online: 31 July 2018 DOI: 10.1051/matecconf/201818401009