Indiana Science HS-PSII-1.3
The Standard
For a system consisting of two objects moving in two dimensions with no net external forces applied, apply the principles of conservation of linear momentum and of mechanical energy to quantitatively predict changes in the linear momentum, velocity, and kinetic energy after the interaction between the two objects.
Indiana Academic Standards for Science (2023) · Energy and Momentum in Two Dimensions
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students split each object's velocity into horizontal and vertical parts. They use momentum totals in both directions to predict motion after an interaction. For elastic interactions, they also use kinetic energy to find or check speeds.
What Mastery Looks Like
- A student calculates missing final velocities, then finds each object's momentum and kinetic energy. They show that total momentum stays the same in each direction and check total kinetic energy when the interaction is elastic.
Common Misconceptions
- Students may add speeds instead of using signed horizontal and vertical momentum. They may think each object's momentum stays the same, or that kinetic energy is conserved in every collision.
How to Assess It
- Give this exit ticket: Two 1 kg pucks collide elastically. A starts at (2, 0) m/s, B starts at rest, and A finishes at (1, 1) m/s. Find B's final velocity, both final momenta, and each puck's change in kinetic energy.
Lesson moves
Ways to Teach It
Roll two marbles across a taped coordinate grid, film the collision from above, and estimate velocities from frame-to-frame positions.
Ask students to write why total horizontal momentum can stay fixed when both pucks leave a collision at angles.
Give pairs cards showing elastic puck collisions with one velocity missing; have them solve both momentum components and check kinetic energy.
Draw a pool shot with two 0.16 kg balls; give the cue ball's before-and-after velocities and calculate the second ball's velocity.
Free download
Printable HS-PSII-1.3 Worksheet
A ready-to-print activity worksheet aligned to HS-PSII-1.3, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetKeep exploring
Related Standards
- HS-PSII-1.1
For a system consisting of a single object with a net external force applied, qualitatively and quantitatively predict changes in its linear momentum using the ...
- HS-PSII-1.2
For a system consisting of two objects with no net external forces applied, qualitatively and quantitatively analyze a two-dimensional interaction (i.e., collis...
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.
Also for this standard:Make a WorksheetMake a QuizMake a Sub Lesson