Packet 9: Bonus 15
Astrophysical plasmas often experience a form of this phenomenon caused by the injection of a hot “stream” of particles. For 10 points each:
[10m] Name this phenomenon in which small perturbations cause a system to rapidly leave equilibrium, which shares its name with a property possessed by the inverted pendulum.
ANSWER: instability [or word forms like unstable; accept two-stream instability]
[10h] The two-stream instability is essentially the inverse of a damping process named for this Soviet physicist, who wrote a Course of Theoretical Physics with Evgeny Lifshitz and ranked the talent of physicists on a log-scale.
ANSWER: Lev Landau [or Lev Davidovich Landau]
[10e] Fluid instabilities occur when a wave’s frequency is one of these numbers, which equal a real number times the square root of negative one.
ANSWER: imaginary numbers [prompt on complex numbers]
<Editors, Physics> | Packet I
| Editions | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|
| 2 | 119 | 12.10 | 92% | 14% | 14% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Durham A | Edinburgh A | 0 | 0 | 10 | 10 | E |
| Durham D | Edinburgh B | 0 | 10 | 10 | 20 | HE |
| Edinburgh C | Durham C | 0 | 0 | 10 | 10 | E |
| Sheffield A | Durham B | 0 | 0 | 10 | 10 | E |
| York | Edinburgh D | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Exact Match? | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|---|---|
| UK (North) | UK | Y | 5 | 12.00 | 100% | 0% | 20% |
| UK (South) | UK | Y | 7 | 14.29 | 100% | 14% | 29% |
| Northern California | US | Y | 4 | 12.50 | 100% | 0% | 25% |
| Southern California | US | Y | 7 | 15.71 | 86% | 29% | 43% |
| Eastern Canada (1) | US | Y | 5 | 12.00 | 80% | 20% | 20% |
| Eastern Canada (2) | US | Y | 9 | 13.33 | 89% | 33% | 11% |
| Florida | US | Y | 4 | 10.00 | 100% | 0% | 0% |
| Great Lakes | US | Y | 12 | 11.67 | 100% | 8% | 8% |
| Lower Mid-Atlantic | US | Y | 9 | 10.00 | 100% | 0% | 0% |
| Upper Mid-Atlantic | US | Y | 2 | 10.00 | 100% | 0% | 0% |
| Midwest | US | Y | 9 | 13.33 | 100% | 22% | 11% |
| North | US | Y | 4 | 12.50 | 100% | 25% | 0% |
| Northeast | US | Y | 10 | 11.00 | 90% | 10% | 10% |
| Pacific | US | Y | 8 | 16.25 | 100% | 38% | 25% |
| South Central | US | Y | 6 | 8.33 | 67% | 0% | 17% |
| Southeast | US | Y | 13 | 10.00 | 77% | 8% | 15% |
| Upstate NY | US | Y | 5 | 12.00 | 100% | 20% | 0% |