A 2.4kg ball falling vertically hits the floor with a speed of 2.5m/s and rebounds with a speed of 1.5m/s. The impact or "collision" described in this problem is:
a. completely elastic
b. completely inelastic
2. The attempt at a solution
As I understand it, the collision in this problem is "inelastic". However, the answer choices make a distinction between "completely elastic" and "elastic" collisions. Since there are no elastic collisions on the macroscopic scale, this cannot be a "completely elastic" collision. Yet, since some macroscopic collisions are approximated as elastic collisions, this might count as an "elastic" collision.
Is the distinction between elastic and completely elastic collisions a legitimate one, or is it there just to throw me off? How would you answer this question?