Students (undergraduate, graduate, high-school,...) and researchers (from academy, industry,...) from all over the world are welcome to send their solutions, discussions and suggestions.

Solutions should be mailed to

[

What's new - a list of latest changes.

D=Discussion, A=Answer, A-=Incomplete answer

# | Title of the Question | D | A |

01/05 | Rope between inclines | A | |

02/05 | Negative index | A | |

03/05 | Against the wind | ||

04/05 | Linear molecules | A | |

05/05 | Pole-vault | ||

06/05 | Sliding box | A | |

07/05 | Bernoulli principle | ||

08/05 | Boiling drop | ||

09/05 | Breaking a thread | A | |

10/05 | Rotation reduction | A | |

11/05 | Polarizable pair of wires | ||

12/05 | Ice in space | ||

01/06 | Bird on a tree |

Many problems given that year were not solved. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/04 | Isotropic universe | A- | |

02/04 | Balancing plank | A | |

03/04 | Frozen Earth | A | |

04/04 | Nonuniform Archimedes | ||

05/04 | Solar sails | A | |

06/04 | Thin ice | D | |

07/04 | Neutral capacitors | ||

08/04 | Falling magnet | D | A |

09/04 | Frictionless rotation | D | A |

10/04 | Wire capacitor | A | |

11/04 | Gas of rotators | D | |

12/04 | High-viscosity motion |

Many problems given that year were not solved. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/03 | Bricks and sticks | A | |

02/03 | Reference frames | A | |

03/03 | Plank on a log | A | |

04/03 | Electric outlet | D | |

05/03 | Leiden jar | ||

06/03 | Meteorites | D | |

07/03 | Hula hoop | D | |

08/03 | Pillow | A- | |

09/03 | Delicate balance | A | |

10/03 | Three-sided coin | A | |

11/03 | Immortal bacteria | ||

12/03 | Three-phase currents | A- |

Several problems given that year were not solved. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/02 | Equipotential surfaces | A | |

02/02 | Maximal gravity | A | |

03/02 | Soap bubble | A | |

04/02 | Scattering dipoles | A | |

05/02 | Line of charges | A | |

06/02 | Isotropic radiator | D | A |

07/02 | Current in a wire | A | |

08/02 | Electrostatic machine | A | |

09/02 | Polymer at a wall | D | A |

10/02 | Least action | A- | |

11/02 | Inviscid motion | ||

12/02 | Charged drop | D | A |

Several problems given that year were not solved. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/01 | Floating sphere | A | |

02/01 | Limited pendulum | A | |

03/01 | Incandescent light | A | |

04/01 | Ball in a box | D | A- |

05/01 | Dipole in a shell | A | |

06/01 | Minimal container | A | |

07/01 | Conducting chessboard | A | |

08/01 | Dandelion seed | ||

09/01 | The power of dimension | D | A |

10/01 | Area maximization | D | |

11/01 | Resistor networks | A | |

12/01 | Bad weather | A |

Solutions of two problems are still incomplete. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/00 | Climbing an iceberg | A | |

02/00 | Halley's planet | A | |

03/00 | Leaning tower of bricks | A | |

04/00 | Bike ride | A | |

05/00 | The first digit | D | A |

06/00 | Hydrogen atom | A- | |

07/00 | Energetics of walk | A | |

08/00 | Radiating sphere | A | |

09/00 | Perpetuum mobile | A | |

10/00 | Charges on a circle | D | A- |

11/00 | Frying in oil | A | |

12/00 | Coaxial cable | A |

Some yet unsolved problems were given that year, and some solutions were incomplete. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/99 | Mind reading | ||

02/99 | Interstellar travel | A | |

03/99 | Half-empty bottle | A | |

04/99 | Cup-a-tea | D | |

05/99 | Circuit of batteries | A | |

06/99 | Stretched molecule | A | |

07/99 | Missing energy | D | A |

08/99 | Zeroth order rainbow | D | A |

09/99 | Mean deflecting force | A- | |

10/99 | 3D billiard | A | |

11/99 | Ohm's law | D | A |

12/99 | Creatures great and small | A |

One yet unsolved problem was given that year, and some solutions were incomplete. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/98 | Delayed weather | D | |

02/98 | A floating triangle | A | |

03/98 | Weighing a fly | A | |

04/98 | Knotted fields | A- | |

05/98 | Unequal halves | A | |

06/98 | Floating bodies of equilibrium | D | A- |

07/98 | Slippery slope | A | |

08/98 | Body heat | A- | |

09/98 | Missing momentum | A | |

10/98 | Falling clouds | A | |

11/98 | Bouncing brick | A- | |

12/98 | Coupled pendulums | A |

Some solutions of the problems given that year were incomplete. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/97 | What causes A/r potential? | D | A |

02/97 | Does voltmeter measure EMF? | - | A |

03/97 | Solvable quantum Hamiltonians | - | A |

04/97 | StatMech in x^{2}+1/x^{2} potential |
- | A |

05/97 | At the lake-shore... | D | A |

06/97 | Breaking windows | A | |

07/97 | Enhancing a jump | A | |

08/97 | Quantifying fog | A | |

09/97 | Lunar Olympics | - | A- |

10/97 | Inertial capillarity | - | A |

11/97 | Variable capacitor | - | A |

12/97 | Once in a blue moon | - | A |

Some yet unsolved problems were given that year. We are still waiting for solutions/discussions/comments

# | Title of the Question | D | A |

01/96 | Running on water | D | A- |

02/96 | Floating faster than a stream | D | A |

03/96 | Candle at night | D | A |

04/96 | Burning Roman ships | D | A |

05/96 | Motion of hockey puck | D | A |

06/96 | Fish versus spermatozoa | D | A |

07/96 | Disintegrating chimney | A | |

08/96 | French flag | - | A- |

09/96 | Avoiding flat tire | D | A |

10/96 | Splashing water | ||

11/96 | Wet spots | A | |

12/96 | Coffee stains | D | A |

If you want to contribute a problem, send it to