A 50,000kg comet is at rest in space. A nuclear explosion spilts the comet into two pieces. If the 35,000kg piece moves away +5m/s, what is the velocity of the second piece?

Answer

-11.67 m/s

Q: What is the total initial momentum of the comet? A: The total initial momentum is 0, since it was at rest.
Q: What is the momentum of the first piece? A: The momentum of the first piece is (35,000 kg)*(5 m/s) = 175,000 kg*m/s.
Q: What is the momentum of the second piece? A: The momentum of the second piece is equal in magnitude but opposite in direction to the first piece, so it is -175,000 kg*m/s.
Q: What is the mass of the second piece? A: The mass of the second piece is 50,000 kg - 35,000 kg = 15,000 kg.
Q: What is the velocity of the second piece? A: The velocity of the second piece can be calculated using the equation p = mv, so v = p/m = (-175,000 kg*m/s)/(15,000 kg) = -11.67 m/s.