- Online Physics Brawl is a three-hour long team competition taking place
on the Internet.
- Participating teams compete in the solving of short physics problems.
The solution to every problem is a number that is sent to our servers
using a web form.
- Teams are awarded points for successfully solved problems. During the
competition, the score of each team is visible to every other team until
20 minutes before the end. At that point, the scores are hidden and not
shown to the participants again until the competition is finished.
Full version of rules
Official announcements to the players from the organisers will be posted
to the noticeboard. Players have to follow this noticeboard.
- Teams consist of 1–5 players.
Every team is a member of one of the following two categories:
- high school students – every team member
must be enrolled in a high school (or in a middle school/elementary
school), and no member can be older than 20 years
- open – everyone who cannot or does not
want to be in the first category.
- Teams solve the same problems no matter what category they are in.
Winners of each category will be announced separately. Absolute winners
will be announced as well.
- Participation in the competition is free.
- The award for the best teams is the eternal fame gained by winning
a competition like this.
- Collaboration among different teams is not allowed.
- While we do monitor the competition and can uncover some methods cheating
but we still are mainly trusting you not to cheat. We assume all the teams
participate because they want to have fun competing. Cheating will spoil
- All members of the team agree with processing their personal information
by registering into the competition. Your information will be used for
appraisal of the competition and its improvement.
- There will be more than 40 problems in the competition (excluding the
hurry up part — see later). The precise amount of problems is
different every year and is not released ahead of time.
- Problems will be available on the web of the competition in the form of
a PDF file. You will
need your team's password to access the problems.
- The answer to a problem is always a number that is delivered via a web
form. Unless otherwise stated, you should assume that this number
is real. The minimum number of significant digits we expect to see will
be stated in each problem. Check this before submitting your answer!
You do not need to worry about numerical inaccuracies, rounding up etc.
since each problem will have a range of correct answers.
- If there is a numerical value of a certain constant in the problem
statement, you should use exactly this value in your calculations.
- Unless otherwise stated, answeres should be expressed in the base
SI units. Examples:
- A train is moving at a speed of 50 km/h. What is the distance it
travels in a minute? State your answer to at least 4 significant
digits. — for example 833,3 or 833,33 are both
- A train is moving at a speed of 50 km/h. How many kilometers will
it travel in a minute? One significant digit is enough.
— for example 0,8
- How many carbon atoms (an integer) does a single molecule of a
cyclopentano-perhydrophenanthrene contain? —
the answer is 17 — 17,0001 is a wrong answer
- The competition will consist of a large spectrum of physics problems.
Some of them will be very easy and some of them really hard. Therefore,
different problems will be worth different amounts of points. The easier
problems will be in the so-called Hurry-up series. However,
you will have only a limited amount of time to solve them.
Rules and the scoring system
The competition consists of three parts (the times are in the UTC+1
- First part: 17:00 to 18:30.
- Second part: 18:30 to 20:00.
- Hurry-up part: 18:00 to 18:30.
- The competition will end at 20:00 (3 hours after it began).
- In the first part, each team will be given the first 7 problems. Once a team
solves a problem, it will gain access to the next problem.
- Teams are awarded points for answering problems correctly. Every problem
specifies a maximum amount of points a team can get by solving it.
You can submit an answer to a problem as many times as you wish. However,
you get the maximum amount of points only if you answer correctly
the first time. If you need one more try, you will only gain 0.6 times
the maximum number of points. If you need three attempts, you will get
0.4 times the maximum and if four, it is 0.2 times the maximum. However,
no matter how many times you try to answer a problem, you will always
get at least one point. The amount of points you get is always rounded up.
- If you answer incorrectly, your team will be disabled to submit any more
answers in the particular group for one minute.
- Second part is essentially the same as the first part. However, teams
will have the opportunity not to answer a given problem and to get
an access to another problem instead. This action will be penalised by
one point. You can skip problems only if you have more than -7 points.
- If two teams happen to end up with the same number of points, the team
who solved their last problem earlier will be considered better and if
it is still a tie then the higher average point gain per problem will
- An hour after the beginning of the competition, teams will be enabled to
answer the problems in the so-called Hurry-up series.
- Teams can submit answers to these problems only during a period of
30 minutes. In this time, you are free to submit answers to the problems
from the first part as well.
- The problems are divided into three groups according to their topic.
When the Hurry-up series is activated, teams are given one problem from
each of these groups. Correctly answering a problem will grant you
access to the next problem in the same group.
- If you correctly answer three problems so that each of them is from
a different group, and they all have the same sequence number in the
corresponding group, you will be given a bonus. This bonus is equal to
the number of points you received for solving this triplet of problems.
- If you answer a problem from the Hurry-up series incorrectly,
the possible amount of points you can get for this particular problem
decreases by one. Therefore, unlike the problems in the first/second
part, you can get zero points for a problem in the Hurry-up
What do I need to participate?
- Access to the Internet (the speed of your connection should not matter).
More than one device with access to the Internet is an advantage but it
is not neccessary. You are allowed to use the Internet as a source of
information that can help you solve the problems. (but you shouldn't use
it to comunicate with people outside the team about the problems.)
- A printer is not neccessary but it might be helpful.
- Papers, pens, literature, calculators, …
- Team mascot.
- Having more people in your team is an advantage. Therefore, we recommend
that you have all five positions filled.
- It is important to decide on a strategy to attack the problems. What
problems can you do quickly? Is it better to work as a team or to divide
the work among individual members? Who decides what individual members
work on? You will have a lot of problems available during the competition
so it is an advantage to know how to approach them as a team beforehand.
- During the competition you will be able to see how other teams are doing
as well as the statistics of each problem. This will end 20 minutes
before the end of the competition. Use this information to figure out
what problems might be easy or hard.
- We suggest occassionally watching the forum for new information as well.
If you don't understand a problem, maybe somebody else has already asked for
a clarification there — and it's faster to read the answer than ask
the same question again!
Code of honour
In case the rules are confusing to you then visit the FAQ section or
contact us via email.
- Even though we hope that the following will never have to be used we
have to include it. The organisers reserve a right to not let a team
sign up, continue in participating or even deleting it from the scoreboards
in the case that fairplay shall be disrupted in some way by said team or
if some detestable behaviour is detected in connection with
- Namely (mainly but not only): if the submitted personal data are false,
vulgar, socially unacceptable, if the team uses inappropriate form of
communicating in the official channels, if the problems are discussed
with people outside of the team during the competition or if an attack
is attempted on the servers of the competition (guessing the passwords
of other teams, intentional spam, unreasonable usage of server time etc.)
- In case of situations that could not be predicted by the organisers or
couldn't be prevented by them, the organisers reserve the power to declare
their final decision on each matter as it comes and this decision will
be made in accordance to the rules of fair play.