Answer:
Two objects with different masses collide and bounce back after an elastic collision.
Welfare means well-being and with a minimum support.
General welfare is the concept that all people should have some basic quality of life (home, food, security).
In order to ensure this, there is often a "general welfare"clause in the constitution (US has it, but other countries too).
I wish i knew, this is a good question to ask on a test
