Physics Cup – TalTech 2021

Final results

Problem 1 – Dumbbell in a magnetic field

Problem 2 – Comet’s orbit

Problem 3 – Oscillating octagon

Problem 4 – Shock wave in an electron gas

Problem 5 – Nonlinear circular resonator

The competition started on December 27th, 2020, at 1 pm (GMT). Please register using this link:!

If you cannot access the registration link due to country-specific restrictions, please send your registration data (full name, date of birth, e-mail address, country, school or university, age group (university/pre-university) physics teacher (if pre-university) by email to

The competition is sponsored by TalTech — Tallinn University of Technology. There is also a budget for awards.

Distribution of problems.

The first problem of Physics Cup – 2020 was published at 1 pm (GMT), 27th December 2020. At 1 pm (GMT) of the last Sunday of each month, between December 2019 and April 2020, a new problem is published at The problems will be sent by e-mail to all the registered participants, too, but I cannot guarantee to send e-mails exactly at 1 pm GMT. Therefore, if you wish to access the problems as soon as possible, please read them online at I’ll send, however, the e-mail with each new problem and with each new hint as soon as I can.

You will be informed if your solution submitted within the previous week was correct or not at 1 pm each Sunday (registered participants will receive an e-mail with a non-public link to a page where all the results are listed).

Also, at 1 pm each Sunday, a new hint regarding the active problem is published at Keep in mind that with each new hint, the base score for correct solutions is decreased by 0.1 pts (for more details, cf.

The final deadline for submitting solutions for the N-th problem is usually when the N+1st problem is published. However, depending on the number of correct solutions, the deadline may be extended by one or two weeks.

About the results of Physics Cup TalTech 2020.

I am very sorry about the long delay with the results of Physics Cup TalTech 2020 – the final results are still not out. The main reason behind this delay is that the COVID-19 disrupted my plans. As a result, I was unable to select the best papers for each problem in time. I can promise that (a) the best papers for the Physics Cup 2021 will be announced within two weeks from the last submission deadline for each of the problems; (b) the final results of the Physics Cup 2020, together with all the best solutions, will be announced during January 2021. – Jaan Kalda

Call for problems. Please send me any problem which you believe would be suitable for Physics Cup (use my personal email – – JK)!