What survives a collision?
Change the trolleys. Predict. Tap one to release both.
Collision apparatus
Right is positive →
Loading apparatus…
Ideal horizontal rail. External horizontal impulse is negligible.
Compare this session
Before and after
Release the trolleys to capture their velocities at contact.
A prediction is optional; the apparatus always follows your settings.
| At contact | A | B |
|---|---|---|
| Just before | ||
| Just after |