Brain-burners

This is the list of the toughest brain-burners on the final exam, in no particular order.

1. "Which way will the compass needle point?" ←was the toughest of all.
   
2. Two balloons attracting each other: might be oppositely charged; might be one charged, one uncharged.
   
3. Baseball trajectories and hang time
   
4. "Suzy vs. Harry" with friction
   
5. "Sliding coin" -- stopping time, stopping distance
   
6. "loop-the-loop"
   

These questions were real bearcats to think out and answer correctly.

I will be posting scores in a few minutes.