This require matmB, or the law of conservation of momentum will not hold OTo find the relation of ma and mB 2 B 1+2 B (m4+ml)= mgu B C 1This require mA=mB, or the law of conservation of momentum will not hold. To find the relation of mA and mB: 2 2 1 2 c u u vB + = 2 2 1 2 ( ) c u m u m m u B A B + + = 2 2 1 c v m m B A B − =