Plan the investigation
What students will do
Use the student handout to organize predictions, measurements, and explanations.
- Predict an elastic collision. Calculate initial total momentum and kinetic energy, and predict each cart’s direction after impact.
- Measure the outcome. Read final velocities and calculate the post-collision totals using signed momentum.
- Make the carts stick. Keep masses and initial velocities unchanged. Predict the shared final velocity, then run a sticking collision.
- Compare the collisions. Evaluate momentum and kinetic energy conservation. Compare the carts’ momentum changes to connect impulse with Newton’s third law.
What students will learn
- Distinguish momentum conservation from kinetic energy conservation.
- Use signed velocities in system calculations.
- Connect interaction forces with equal and opposite impulses.
Common misconception
Is kinetic energy conserved in every collision?
Students compare elastic and sticking outcomes while accounting for the same initial system momentum.