... ) 2 + (1 /2) . m 1 . 2 .r 1 2 /2 + (1 /2) .m 2 .(( (r 1 + r 2 .t)) 2 + (r 2 ) 2 ) = 2 [0,5.m 1 ..r 1 2 + 0 ,25 . m 1 ..r 1 2 + 0,5. m 2 .(r 1 2 + 2. r 1 .r 2 t+ r 2 .t 2 )] + r 2 2 .[0,5.m 2 .] ... hợp : M 1 = 2. (r 2 .t + r 1 .r 2 )m 2 = 2. /15 .2, 5.0 ,2. 5 + 2. /15 .2, 5.0,5.0 ,2 = 0 ,26 1 + 0. 026 1 (N.m) = 0 .28 71(Nm) F 2 = 2. m 2 .r 2 .t + m 2 .r 1 . = 2. 2,5.0 ,2. 5 + 2, 5.0,5.0 ,21 = 5 ,26 (N) Sinh ... (d/dt) {2. . (0,75.m 1 ..r 1 2 + 0,5. m 2 .(r 1 2 + r 2 .t 2 ))} 0 = 2. (r 2 .t + r 1 .r 2 )m 2 F 2 = (d/dt){L/r 2 } ( L/r 2 ) = (d/dt) {2. r 2 .[0,5.m 2 .t 2 + 0,5.m 2 ]} 0 = 2. m 2 .r 2 .t...