The solution before revision #20601 of , by Tete. This is not the current version.
After it Changes Current version

Statement

2.2.18. [Insert the problem statement]

For problem $2.2.18$

Solution

For problem $2.2.18$
For problem

Since total momentum of the system is zero, the center of mass (C.M.) remains stationary. The C.M. is on the line segment joining the two particles so that it is twice as far from the particle with mass as it is from the particle with mass . Thus, the trajectory of the particle with mass is obtained by reflecting the trajectory of the particle with mass across the C.M. and enlarging it by a factor of 2.

Answer

[Insert a concise answer or boxed result]