Elastic Collision, explained.
A perfectly elastic collision conserves both total momentum and total kinetic energy in an isolated system.
Why it happens
Cart A begins at four metres per second and B at rest. The one-dimensional two-mass solution computes both final velocities and independently displays momentum and energy.
A perfectly elastic collision conserves both total momentum and total kinetic energy in an isolated system.
Read the result
Check momentum and energy totals as well as individual speeds. A negative final velocity means reversal along the selected one-dimensional axis.
A worked example
Swap velocities with equal ideal masses
Set both cart masses to one kilogram and resolve the collision.
Inspect A stopping and B taking the original four-metre-per-second velocity.
Raise B’s mass and repeat, observing A’s possible rebound while the total conserved quantities remain unchanged.
OPTIONAL DEEPER DETAILGo deeper: inside the model
Inside this model
Cart A begins at four metres per second and B at rest. The one-dimensional two-mass solution computes both final velocities and independently displays momentum and energy.
Where this idea is useful
A practical use
Predict why equal ideal masses exchange velocities while a light cart can rebound from a heavier one.
A common misconception
“Conserving momentum alone makes a collision elastic.”
An elastic collision also conserves kinetic energy. Other collisions can conserve momentum while dissipating kinetic energy into internal modes.
What this explanation leaves out
- Point-cart one-dimensional motion, no external impulse and no energy dissipation are assumed. The drawing is a schematic before/after view, not a contact-dynamics simulation.
What does a rebound’s negative sign represent?
It is motion opposite to the initial positive axis, not negative speed magnitude or negative kinetic energy.
Which conserved total can distinguish the collision models you are comparing?
Associated thinkers
Associations marked provisional are awaiting source review.
Further reading
Explore the original research or the teaching reference behind this experiment.