A 120 Kg Mass, Initially at Rest, Is Blown Apart

Multiple Choice

A 120 kg mass, initially at rest, is blown apart into a 80 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The speed of the 80 kg mass is

A) 59 m/s.
B) 51 m/s.
C) 34 m/s.
D) 20 m/s.
E) 14 m/s.