Clarification Statement - S.HS.PS.2.2.CS:
Emphasis is on the quantitative conservation of momentum in interactions and the qualitative meaning of this principle.

Assessment Boundary - S.HS.PS.2.2.AB:
Assessment is limited to systems of two macroscopic bodies moving in one dimension.

Science and Engineering Practices - 9-12.SEP5.2:
Use mathematical representations of phenomena to describe explanations.

Disciplinary Core Ideas - S.HS.PS.2.2.DCI:
PS2.A: Forces and Motion •Momentum is defined for a particular frame of reference; it is the mass times the velocity of the object. •If a system interacts with objects outside itself, the total momentum of the system can change; however, any such change is balanced by changes in the momentum of objects outside the system.

Crosscutting Concepts - CC3.5:
When investigating or describing a system, the boundaries and initial conditions of the system need to be defined.