If a system feels any external force, must it then by necessitynot satisfy conservation of momentum? What if it feels two suchexternal forces that happen to balance? What if it feels two suchexternal forces that happen to balance in just (say) thex-direction but do not balance in (say) the y-direction?
For a system that’s initially at rest (zero initial totalmomentum and zero initial kinetic energy) but then ends up withmultiple objects moving (non-zero final total momentum and non-zerofinal kinetic energy), what would you have to do to useconservation of mechanical energy in order to determine info aboutthe objects’ velocities?
