HS-PS2-2

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Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.

Clarification statement: Emphasis is on the quantitative conservation of momentum in interactions and the qualitative meaning of this principle.

Assessment boundary: Assessment is limited to systems of two macroscopic bodies moving in one dimension.

Regents Exam Questions

Released New York State Regents exam questions that assess HS-PS2-2 are listed here by exam and question cluster. Each link opens the question with its answer key.

Exam	Cluster	Question
June 2026 Physics Regents	From Astro Blaster to Supernova	Question 38

Vocabulary

Terms from the Physics Glossary that come from this standard or from the released exam questions that assess it.

From this standard

• boundaries of a system
• boundary
• claim
• conservation of momentum
• direction
• force
• frame of reference
• initial conditions
• interaction
• macroscopic bodies
• mass
• mathematical representation
• momentum
• net force
• object
• one dimension
• qualitative
• quantitative
• speed
• support (a claim)
• system
• system of objects
• total momentum
• velocity

From released exam questions

• before and after collision – June 2026
• collision – June 2026
• computer simulation – June 2026
• law of conservation of momentum – June 2026
• rebound – June 2026
• refute – June 2026
• significant digits – June 2026
• simulation – June 2026

Performance Level Descriptions

Every Regents exam question on HS-PS2-2 is written to match one of the performance level descriptions (PLDs) below.

Level 1: Given data and/or a model, use a mathematical representation for momentum to identify the mass, or the momentum (with or without direction), or the velocity/speed of an object.

Level 2: Given data and/or a model, use a mathematical representation to determine the total momentum, with or without direction, of a system of objects before or after an interaction when there is no net force on the system.

Level 3: Given data and/or a model, use a mathematical representation for the conservation of momentum to determine the mass and/or velocity of an object before or after an interaction between two objects when there is no net force on the system.

Level 4: Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system. June 2026 · Q38

Level 5: Collect and analyze data and use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.

Notice: PLD levels!

Resources

Examples and discussion of resources for the learning, teaching, and assessment of HS-PS2-2.

This section could be expanded upon. You can help out by adding to this section.

NGSS Dimensions

Performance expectation HS-PS2-2 was developed using the following elements from the NRC document A Framework for K-12 Science Education:

Science and Engineering Practices

• Using Mathematics and Computational Thinking
  • Use mathematical representations of phenomena to describe explanations.

Disciplinary Core Ideas

• 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

• Systems and System Models
  • When investigating or describing a system, the boundaries and initial conditions of the system need to be defined.

Page contributors: Caroline Leonard, Conrad Richman

Physics | HS. Forces and Interactions