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    • Physics Cup - TalTech 2025
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      • Problem 1 - Magnetized ball
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      • Problem 1 - Dumbbell in a magnetic field
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    • Physics Cup – TalTech 2020
      • Problem 0 - Sheet resistance
      • Problem 1 - Small oscillations of a system in an electric field
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    • Physics Cup – TalTech 2019
      • Problem 1 - Added mass
      • Problem 2 - Heat engines
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      • Problem 1 - Lattice of resistors
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      • Problem 4 - V-shaped vessel
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    • Physics Cup – 2017
      • Problem 1 - Interaction force
      • Problem 2 - N-gon resistance
      • Problem 3 - Electron gas temperature
      • Problem 4 - Lens position
    • Physics Cup – WoPhO 2013
      • Problem 1 - Dodecahedron capacitance
      • Problem 2 - Ring on rails
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      • Problem 4 - High-effciency LED
      • Problem 5 - Magnetic levitation
    • Physics Cup – IPhO 2012
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Problem 4 – Hint 4

Kinetic energy can be reduced to a boundary integral.

Please submit the solution to this problem via e-mail to physcs.cup@gmail.com.

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