International
Online
Physics Competition

Thank you for 15 years of support.

1228 participated teams from 74 countries
Important Announcement

Announcement of the End of Physics Brawl Online

Dear participants, teachers, and physics enthusiasts,

After fifteen years, we are saying goodbye to Physics Brawl Online.

This was not an easy decision. Today, artificial intelligence tools are able to solve our competition problems at a level comparable to that of high-school students, or better. As these tools continue to develop, the online competition in its current form is losing its purpose. We do not want Physics Brawl Online to become a prompting competition, nor do we want honest participants to lose motivation because they see others around them cheating.

More than a year ago, we sent out questionnaires to you and discussed various ways to keep the competition going under these circumstances. After long discussions, we addressed the situation transparently, introduced changes to the rules, and, among other things, held video calls with selected teams to verify their solutions. However, in the 2025 contest, after a thorough investigation, we disqualified 175 teams, and we have reasonable grounds to suspect that many others used AI as well, although we are unable to prove it. Although we do not wish to disclose all the methods we used to investigate cheating, we consider it important to emphasize that we devoted considerable effort to detecting dishonest behaviour: we carefully reviewed patterns of behaviour by hand and gathered evidence for hundreds of teams. In the end, however, we came to the conclusion that even the measures we had introduced were not enough, and that most of the other proposed solutions would either be almost technically impossible to implement or would go against the fundamental idea of the competition: to make physics accessible to everyone who is interested.

Over the fifteen years of its existence, Physics Brawl Online grew into the largest event of its kind in the world. In its most successful year, 1,574 teams from 81 countries took part. More than once, we encountered someone who knew FYKOS, or even the Czech Republic, precisely and only because of this competition. For us as organizers, this was an immensely humbling and beautiful experience, and it taught us a great deal – from unifying conditions for school systems across the world to the technical challenges of thousands of devices connecting at the same time. For all of this, we owe our thanks above all to you: the participants, teachers, and all generations of organizers who gradually built the competition and shaped it into what it is today.

That is why we want to bring it to a close with dignity and with our heads held high. This step will also allow us to focus our efforts on our other activities. The archive of competition problems from previous years will remain available on the website. And who knows – perhaps one day Physics Brawl Online will return in a new form.

Thank you to everyone who made Physics Brawl Online a phenomenon. We look forward to meeting you again somewhere else.

On behalf of the entire organizing team,

Vojtěch David
President of the Central Committee
of Physics Brawl Online
Monika Drexlerová
Head Organizer of Physics Brawl Online
Jiří Sýkora
Deputy Head Organizer of Physics Brawl Online
David Škrob
Head Organizer of FYKOS
Rules briefly

What is Physics Brawl Online?

Up to five high school students compete from their homes by solving physics problems in a three-hour-long contest, though anyone can take part in the Open category: a teacher, university student or just a fan of physics.
There are seven problems always available. As soon as a team solves one correctly, they recieve another problem. For each solved problem, the team is awarded points.
The best teams win prizes and undying glory in our competition, which has been held annually for over a decade now.
Rules
Problem examples

Everyone Finds Their Level of Difficulty

Consider a street lamp of height H = 3.2 m as a point source of light. A person of height h = 1.8 m is walking in a straight line directly away from the lamp at a constant speed of v = 1.5 m·s−1. Calculate the acceleration of the top of their shadow.
We have a transmission line with high voltage U0 = 110 kV, and we would like to increase it to extra-high voltage U1 = 400 kV. Assuming the resistance of the line is constant, how much will the power losses on the line change? We are interested in the power loss ratio P1/P0.
What would be the air pressure at sea level if the Earth had an atmosphere with the same temperature lapse rate as it does today (i.e., a linear decrease of temperature by 0.65 °C per 100 m altitude), but at an altitude H = 8 850 m above sea level (on Mount Everest), the pressure pa would be the same as it is today at sea level? Consider the sea level temperature T0 = 15 °C.
To maximize the frictional force between the wheels of Formula 1 cars and the road surface, the car body is designed so that air resistance pushes the car to the ground. At what speed would the Formula 1 cars have to travel in order to drive heads down on the ceiling? For simplicity, consider that the car is a right-angled triangle of length 5.1 m, height 1.0 m, and width 1.8 m. The vehicle’s mass, including the driver, is 800 kg. Let us further assume that the air particles are initially stationary and elastically bounce off the vehicle.
Hall of fame

Winners of the previous years

2025
SciTech
Ahmet Cemal Usta, İhsan Yağız Kara, Kaan Güngör, Eyüp Efe Şimşek, Mert Andaç Karan
2024
важното е да сме живи и здрави
Stefan Ivanov, Georgi Aleksandrov, Aleksandar Prodanov, Yavor Yordanov, Ivan Popov
2023
Puddle
Vishal Kannan, Wenkai Liu, Shanay Jindal, Luc Mazereeuw, Le Xi Ng
2022
S.I.M.P.S.
Đức Huy Trần, Eddie Chen, Quan Nguyen, Tung Tran, Zhening Li
2021
Metaphysical Brawlers
Đức Huy Trần, Nam Nguyen Hoang, Mạnh Quân Nguyễn, Tung Tran, Ung Nguyen
2020
The Large Noobs Collider
Tung Tran, Mạnh Quân Nguyễn, Đức Huy Trần, Tan Nguyen, Ung Nguyen
2019
Temple of Next
Anthony Ou, David Xiong, Vincent Bian, Raymond Li, Sanjay Raman
2018
NOFY066
Patrik Švančara, Jan Brandejs, Jakub Kocák, Jan Sopoušek, Ján Pulmann