For a system of particles of constant total mass M, which statements are correct?
Select all that apply

Question

For a system of particles of constant total mass M, which statements are correct?

G1 Physics · Accepted Answer

For a constant-mass system, the vector sum of external forces satisfies F(ext) = M a(CM). Internal forces cancel in pairs in the total momentum equation and therefore cannot change the total momentum of an isolated system. If F(ext)=0, then a(CM)=0 and v(CM) is constant. Individual particles can still accelerate due to internal forces even while their weighted-average acceleration is zero. Hence A, C and D are correct.