1. The problem statement, all variables and given/known data The 3rd and 4th stages of a rocket, mass 40kg and 60kg respectively, coast in space with a velocity of 15,000kmh when the 4th stage ignites, with thrust T and causes separation. If the velocity of the 4th stage is 10m/s greater than the 3rd stage at the end of the 0.5 second separation interval calculate the average thrust during this period. Assume the entire blast impinges against the third stage with a force equal and opposite to T. 2. Relevant equations Ft=m(v2-v1) (m1u1+m2u2) = (m1v1+m2v1) 3. The attempt at a solution I have used the ft=m(v2-v1) formula, answer 2000N, I don't believe this is correct.