An atomic nucleus suddenly bursts apart (fissions) into two pieces. Piece A, of mass mA' travels off

Question:

An atomic nucleus suddenly bursts apart (fissions) into two pieces. Piece A, of mass mA' travels off to the left with speed VA Piece B, of mass mB, travels off to the right with speed VB' (a) Use conservation of momentum to solve for VB in terms of mA, mB, and VA-
(b) Use the results of part
(a) To show that K, JKB = mB/mA, where KA and KB are the kinetic energies of the two pieces.