Exercise your mind! One challenging problem is posed each month.
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 kantor@post.tau.ac.il. The best (and, hopefully, correct) solution will be published on this WWW server.
[Please, ask your webmaster or equivalent computer-wiz to include a reference (link) to this page in the appropriate web page of your organization.]

What's new - a list of latest changes.

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

2005/06
#Title of the QuestionDA
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


2004
Many problems given that year were not solved. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
10/04 Wire capacitor A
11/04 Gas of rotators D
12/04 High-viscosity motion


2003
Many problems given that year were not solved. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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-


2002
Several problems given that year were not solved. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
07/02 Current in a wire A
08/02 Electrostatic machine A
09/02 Polymer at a wall DA
10/02 Least action A-
11/02 Inviscid motion
12/02 Charged drop DA


2001
Several problems given that year were not solved. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
10/01 Area maximization D
11/01 Resistor networks A
12/01 Bad weather A


2000
Solutions of two problems are still incomplete. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
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 DA-
11/00 Frying in oil A
12/00 Coaxial cable A


1999
Some yet unsolved problems were given that year, and some solutions were incomplete. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
08/99 Zeroth order rainbow DA
09/99 Mean deflecting force A-
10/99 3D billiard A
11/99 Ohm's law DA
12/99 Creatures great and small A


1998
One yet unsolved problem was given that year, and some solutions were incomplete. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA-
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


1997
Some solutions of the problems given that year were incomplete. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
01/97 What causes A/r potential? DA
02/97 Does voltmeter measure EMF? -A
03/97 Solvable quantum Hamiltonians -A
04/97 StatMech in x2+1/x2 potential -A
05/97 At the lake-shore... DA
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


1996
Some yet unsolved problems were given that year. We are still waiting for solutions/discussions/comments
#Title of the QuestionDA
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 DA
06/96 Fish versus spermatozoa DA
07/96 Disintegrating chimney A
08/96 French flag- A-
09/96 Avoiding flat tire DA
10/96 Splashing water
11/96 Wet spots A
12/96 Coffee stains DA




List of other sites with problems/puzzles




If you want to contribute a problem, send it to kantor@post.tau.ac.il