Question

find the condition of 1-D elastic collison and then find out their final velocity.with S.P. cases.

Answer 1

1-d collsion means the bodies colliding move in a single straight line(may be same or different direction)
using momentum conservstion work out the velocities

momentum conservation:
total initail momentum of bodies=total final momentum of bodies

since the collision in 1-d u wont have that much trouble as the velocities wud be in same or opposite directions