International
Online
Physics Competition

Sign up with a team of up to five members.
Registration is open until November 26, 13:00 CET.

About Register
151 registered teams from 31 countries
Please note that the rules have been modified since last year. You can find the current version in the Rules tab.
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
What are the prizes?

Prizes Prepared for the Best of You.

FYKOS's bottles,
T-shirts and other prices Brilliant
premium
OriginPro AoPS
licence
PhysOlymp
licence
We are preparing more prizes...
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.
Competition schedule

The contest takes place on Wednesday November 26, 2025

Beginning of the contest

Participants get 7 problems. Once they solve any of them, they immediately get another.

Hurry-up

Another series of problems appears, with problems related to different physics fields. For the next half an hour, participants can achieve bonus points for solving the series.

End of bonus points in the Hurry-up series

Problems from Hurry-up are still available but without bonus points.

End of the competition

The competition is over. We publish the author's solutions and settle potential conflicts. At the same time, we send invitations to video calls to the selected teams.

Start of video calls

The first teams join the video calls.

End of sending invitations

All invitations to video calls have been sent and no further ones will follow.

Deadline for complaints

We close the possibility to complain.

End of video calls

We finish the last calls and prepare to publish the official winners during the upcoming days.

Registration

Sign up and become a legend!

  • Participation is free for anyone!
  • Registration is open from September 1 until November 26, 13:00 CET.
  • Except for communicating with other teams and generative AI, you can use any tools to solve the problems.
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
2017
FtáKopySk -fks.sk
Dušan Kavický, Filip Kubina, Matej Badin, Jakub Cimerman, Michal Hledík