what is collision in one dimension?

Answer 1

A not so big bang.

Can we have some detail to reference?

Answer 2

collision in one dimension means if a body collides with another body in rest and the second body is moving in the same direction in which the force is applied
for example consider a particle is kept on the origin of a grph paper and a force is applied along x axis then if the object moves along the x axis itself without any deviation then the body is said to be expressing collision in one dimension