Two neon atoms of identical mass move along a straight line toward each other. Atom 1 moves to the right at 300m⋅s−1, while atom 2 moves to the left at 100m⋅s−1. They collide elastically and head-on. What is the speed of atom 1 immediately after the collision?
a) 300m⋅s−1 to the left
b) 300m⋅s−1 to the right
c) 100m⋅s−1 to the left
d) 100m⋅s−1 to the right