Predict the physics: what happens when you let go?

Questions

1. 1
   Not answered. You pull one end of a long bead chain out of a jar on a high shelf and let it fall to the floor. Once the chain is flowing, what happens where it leaves the jar?
2. 2
   Not answered. Tension pulls along a chain, so it cannot lift a bead above the rim it is being pulled over. Where does the upward force on the beads come from?
3. 3
   Not answered. You move the same jar and chain from a shelf 1 m above the floor to a shelf 2 m above it. What happens to the height of the arc above the jar?
4. 4
   Not answered. You run the experiment again with a limp silk cord of the same mass per metre in place of the bead chain. What do you see?
5. 5
   Not answered. A drop of water on a pan at 150 °C is gone in a second or two. You heat the same pan to 250 °C and add an identical drop. How long does this one last?
6. 6
   Not answered. Why does the hotter pan take so much longer to boil the same drop away?
7. 7
   Not answered. Roughly how hot does a smooth steel surface have to be before a water drop stops wetting it and starts to levitate on its own vapour?
8. 8
   Not answered. A hot plate well above the Leidenfrost point is machined with sawtooth teeth that all lean the same way. You set a levitating drop down on it. What does the drop do?
9. 9
   Not answered. A pot of water with an electric heater in it is already boiling hard. You keep dialling the power up. What happens to the temperature of the heater's own surface?
10. 10
    Not answered. A cosmonaut spins a T-shaped handle about its intermediate axis and lets it float free. What does the handle do next?
11. 11
    Not answered. Which free spins of a rigid body with three different moments of inertia hold their orientation?
12. 12
    Not answered. While the handle flips over and back, nothing touches it. Which of these stay constant?
13. 13
    Not answered. You toss a phone three ways: a flat spin about the axis out of the screen, a roll about the axis down its long edges, and an end-over-end flip about the axis across its short edges. Which toss lands with the screen facing the other way?
14. 14
    Not answered. Explorer 1 launched in 1958 spinning at 750 rpm about its long axis, the axis with the smallest moment of inertia. It was soon tumbling instead. What went wrong?
15. 15
    Not answered. Three frictionless tracks join the same two points, A above and B lower and off to one side. Identical balls start from rest on all three at the same instant. Which one reaches B first?
16. 16
    Not answered. The winning track is longer than the straight ramp. Why does the extra distance not cost it the race?
17. 17
    Not answered. What is the name of the curve that solves this problem, the one traced by a point on the rim of a wheel rolling along a straight line?
18. 18
    Not answered. You release two beads from rest at different heights on the same cycloid trough. Which one reaches the bottom first?
19. 19
    Not answered. Now B sits far off to the side. The sideways distance from A is three times the drop from A down to B. Where does the fastest frictionless track go?