Collisions -- in-class lab exercises

I've had considerable success this year with 9th graders replacing quantitative demonstrations with in-class laboratory exercises.  Everyone individually solves a problem at his desk; when I approve the solution, each student in turn goes to the back of the room where the solved problem serves as a prediction to an actual laboratory setup.

We've gone through this process with position-time graphs; velocity-time graphs; direction of force and motion; friction forces; forces in 2-d; collisions; impulse; and energy.

Eventually I will proofread all of these, compile them, make sure they work in multiple years, and publish them all.  But for now, I offer this set of collision problems.  These are particularly easy to set up if you have PASCO carts and tracks.  

Posts I intend to write soon:  The baseball schedule is pretty crazy right now.  I'm umpiring or broadcasting five games a week for the next month.  Yet I am still here and willing to write about physics!  Soon, perhaps, I will get to:

* Why the in-class lab exercises have worked well in ninth grade, but I have no intention of every trying them in 12th grade classes

* a fishing line experiment with impulse

* Our overall, full-year conceptual physics outline -- would you like to take our exam?

* Any and all of your AP physics 1 questions, after I get back from the April 20-21 consultant training.

Please send any other requests via email, and I'll see what I can do.

GCJ