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k a May Highlights and 2025 AoPS Online Class Information

jlacosta 0

May 1, 2025

May is an exciting month! National MATHCOUNTS is the second week of May in Washington D.C. and our Founder, Richard Rusczyk will be presenting a seminar, Preparing Strong Math Students for College and Careers, on May 11th.

Are you interested in working towards MATHCOUNTS and don’t know where to start? We have you covered! If you have taken Prealgebra, then you are ready for MATHCOUNTS/AMC 8 Basics. Already aiming for State or National MATHCOUNTS and harder AMC 8 problems? Then our MATHCOUNTS/AMC 8 Advanced course is for you.

Summer camps are starting next month at the Virtual Campus in math and language arts that are 2 - to 4 - weeks in duration. Spaces are still available - don’t miss your chance to have an enriching summer experience. There are middle and high school competition math camps as well as Math Beasts camps that review key topics coupled with fun explorations covering areas such as graph theory (Math Beasts Camp 6), cryptography (Math Beasts Camp 7-8), and topology (Math Beasts Camp 8-9)!

Be sure to mark your calendars for the following upcoming events:
[list][*]May 9th, 4:30pm PT/7:30pm ET, Casework 2: Overwhelming Evidence — A Text Adventure, a game where participants will work together to navigate the map, solve puzzles, and win! All are welcome.
[*]May 19th, 4:30pm PT/7:30pm ET, What's Next After Beast Academy?, designed for students finishing Beast Academy and ready for Prealgebra 1.
[*]May 20th, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 1 Math Jam, Problems 1 to 4, join the Canada/USA Mathcamp staff for this exciting Math Jam, where they discuss solutions to Problems 1 to 4 of the 2025 Mathcamp Qualifying Quiz!
[*]May 21st, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 2 Math Jam, Problems 5 and 6, Canada/USA Mathcamp staff will discuss solutions to Problems 5 and 6 of the 2025 Mathcamp Qualifying Quiz![/list]
Our full course list for upcoming classes is below:
All classes run 7:30pm-8:45pm ET/4:30pm - 5:45pm PT unless otherwise noted.

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0 replies

jlacosta

May 1, 2025

0 replies

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i A Comprehensive List of Physics Olympiad Resources

Lol_man000 177

N Aug 13, 2024 by enya_yurself

A Comprehensive List of Physics Olympiad Resources

Before I start, I would advise everyone to read this link for lots of advice on starting and learning physics.

Updates

Introductory Physics Books
[list]
[*] Physics by Halliday Resnick Krane (Calculus-based) Harder version of HRW with about 1/3 more harder material added to each chapter. Previous editions were edited by former USAPhO coach. This book covers almost all the material required for physics olympiads and is recommended by many coaches and teachers alike.
[*] Fundamentals of Physics by Halliday Resnick Walker (Calculus-based). Easier version of Halliday Resnick Krane (HRK, see above).
[*] Physics: Principles with Applications by Giancoli (Algebra-based)
[*]Physics for Scientists and Engineers by Randall D. Knight (Calculus-based).
[*] University Physics by Young. Similar to HRK, it covers a lot of the first year undergraduate sequence and contains loads of information.
[/list]

Subject Specific Books
[list]
[*] An Introduction to Classical Mechanics by David Morin. Comment (USAPhO/IPhO, some chapters are relevant to F=ma practice)

[*] Electricity and Magnetism by Purcell and Morin. Comment (USAPhO/IPhO)

[*] Introduction to Electrodynamics by David J. Griffiths. Comment (USAPhO/IPhO)

[*] Concepts in Thermal Physics by Stephen J. Blundell, Katherine M. Blundell. Comment (USAPhO/IPhO, some chapters are too high level for IPhO)

[*] An Introduction to Mechanics by Kleppner and Kolenkow. (USAPhO/IPhO, some chapters are relevant to F=ma practice). Comment

[*] Vibrations and Waves by A.P French. Comment (USAPhO/IPhO, some chapters are too high level for IPhO)

[*] Thermal Physics by Daniel Schroeder. (USAPhO/IPhO, some chapters are too high level for IPhO) Comment

[*] Modern Physics by Kenneth S. Krane
[/list]
Problem Books/Handouts
[list]
[*] Problems and Solutions in Introductory Mechanics by David Morin (A good book for preparing to the F=ma exam and for practicing basic mechanics)
[*] 200 More Puzzling Physics Problems by Peter Gnadig.
[*] Pathfinder for Olympiad & JEE:Physics by Arwind Tiwari/Sachin Singh. Comment
[*] Problems in General Physics by I.E Irodov.
[*] Jaan Kalda's Handouts by Jaan Kalda (F=ma to IPhO Level Problems) (solutions are found here)
[*] Physics Olympiad - Basic to Advanced Exercises by The Committee Of Japan Physics Olympiad Japan
[*] Competitive Physics: Mechanics and Waves by Wang and Ricardo
[*] Competitive Physics: Thermodynamics, Electromagnetism and Relativity by Wang and Ricardo.
[*] Thinking Physics by Lewis Carroll Epstein (a book of conceptual problems for beginners and intermediate-levels)
[*] 200 Puzzling Physics Problems by Gnadig (USAPhO / IPhO level problems)
[*] Aptitude Test Problems in Physics by S.S Krotov.
[*] 300 Creative Physics Problems with Solutions by Holics (USAPhO / IPhO level problems)
[*] Physics to a Degree by Thomas and Raine (USAPhO / IPhO level problems)
[*] Thinking Like a Physicist by Thompson (USAPhO / IPhO level problems)
[*] F=ma Solutions Manual by Branislav Kisacanin and Eric K. Zhang.
[*] Feynman's Lectures on Physics.
[*] 1000 Solved Physics Problems by Kamal
[/list]

List of Physics Contests
[list]
[*] IPhO Comment
[*] EuPhO Comment
[*] F=ma Exam Comment
[*] USAPhO Comment
[*] Physics Bowl Comment
[*] BAUPC Comment
[*] Pan Pearl River Delta Physics Olympiad Comment
[*] HKPhO
[*] NBPhO
[*] IZhO
[*] Physics Cup Comment
[*] OPhO Comment
[*] Sir Isaac Newton Exam
[*] FYKOS Internet Physics Competition
[*] INPhO
[*] APhO
[*] BPhO
[*] AuPhO
[*] Princeton University Physics Competition
[*] Gulf Physics Olympiad
[*] Online Physics Brawl
[*] PUEC
[*] JPhO (in Japanese)
[*] SwissPhO
[*] Moscow City Physics Olympiad (In Russian)
[*] MIPT (Fiztekh) Physics Olympiad (In Russian)
[*] Saint Petersburg Physics Olympiad (In Russian)
[*] Belarusian Physics Olympiad (In Russian)
[*] EstPhO (in Estonian)
[*] Eötvös Competition (in Hungarian)
[*] Fizika
[*] The University Physics Competition
[*] Rudolf Ortvay Competition in Physics
[*] ThWorldCup
[/list]

Other Resources
[list]
[*] Kevin Zhou's Olympiad Handouts Comment
[*] Physics Olympiad Hub Comment
[*] Everaise Academy Physics Classes Comment
[*] Physics WOOT created by AoPS.
[*] F=ma Problem Series Class created by AoPS.
[*] PhysOlymp
[*] KöMaL Magazine (in Hungarian)
[*] Quantum Magazine.
[*] Physics Genie
[*] Upgrade Your Physics by BPhO.
[*] MIT OCW 8.01 (Classical Mechanics)
[*] MIT OCW 8.02 (Electricity and Magnetism)
[*] MIT OCW 8.03 (Vibrations and Waves/Optics)
[*] AwesomeMath Physics Classes.
[*] Isaac Physics.
[*] Physics Stack Exchange
[*] AoPS Physics Forums :P
[/list]

Summer Camps & Other Opportunities (In progress)
[list]
[*] If you are interested in doing research, consider looking at summer programs offered by your local universities! Many offer one and you can have an internship working with a professor over the entire summer and potentially during the school year as well. If not, cold emailing is also a great option.
[*] Summer Science Program (SSP)
[*] Research Science Institute (RSI)
[*] Quantum School for Young Students (QSYS)
[*] International Summer School for Young Physicists (ISSYP)
[*] Boston University RISE
[*] Summer Program on Applied Rationality and Cognition (SPARC)
[*] High School Honors Science, Math and Engineering Program (HSHP)
[*] University of Florida Student Science Training Program
[*] Texas Tech Clark Scholar Program
[*] Center for Astrophysics, Space Physics & Engineering Research (CASPER)
[*] Yale Summer Program in Astrophysics
[*] MIT Introduction to Technology, Engineering, and Science (MITES)
[*] Garcia Summer Program
[*] George Mason University Aspiring Scientists Summer Internship Program (ASSIP)
[*] Note: I would shy away from "pre-collegiate" summer programs at prestigious universities that have you pay because they are typically a grab for money (6-7k+) and don't really teach you very much (also they admit most students that apply). They don't look that great for a college application either.
[/list]

177 replies

Lol_man000

May 9, 2020

enya_yurself

Aug 13, 2024

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Feynman's Tips on Physics: Section 1, Problem 1 (Conservation of Energy)

anticodon 0

3 hours ago

(I thought I'd include the problems in this forum for anyone who is interested in them but the book itself is unavailable. This is the 1st problem under Conservation of Energy, Vol 1 chapter 4 of the Feynman Lectures on Physics. Probably the easiest problem there is)

[quote]
A ball with weight $1.00$ kg rests against a vertical wall and a plane inclined at an angle $\theta$ with respect to the horizontal. What is the force the ball is exerting on each wall?
[/quote]

WRITTEN DIFFICULTY (the difficulty marked in the book): Easy
PERCIEVED DIFFICULTY (what I think the difficulty was): Easy

my solution

0 replies

anticodon

3 hours ago

0 replies

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Physics "Tricks"

neeyakkid23 5

N May 28, 2025 by anticodon

Hey guys. I've noticed that there are a decent number of "tricks" in physics problems that can help boost speed and efficiency. An example of which would be:
- One mass colliding with an identical mass at rest will transfer all of its momentum at that angle to it
Is there a list of tricks I should know or are there any other tricks I should know?

5 replies

neeyakkid23

Mar 20, 2025

anticodon

May 28, 2025

J

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Question

Riptide1901 2

N May 27, 2025 by whoosh

I'm confused about part (c) of question B2 of the 2025 USAPhO.

How do they know that the horizontal distance between the wave front that hits the top detector and the one that hits the bottom detector is $vt\,?$

2 replies

Riptide1901

May 26, 2025

whoosh

May 27, 2025

J

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Question

Riptide1901 4

N May 26, 2025 by Riptide1901

I'm confused about part (d) of problem A3 of the 2025 USAPhO.

In the last line they said that the square of the maximum field inside the solenoid would be
$\sum_{k=1}^N(B_k^2-B_{k-1}^2).$ I'm confused where they got this from. Wouldn't the maximum field inside the solenoid just be the sum of the individual contributions of magnetic field from each layer $1$ through $N\,?$ So shouldn't the relation be
$B_N=\sum_{k=1}^N B_k\,?$

4 replies

Riptide1901

May 25, 2025

Riptide1901

May 26, 2025

J

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Question

Riptide1901 0

May 26, 2025

I have a question about part (b) of question B1 on the 2025 USAPhO.

Due to momentum conservation, the CM of the system has to stay in place, and therefore the ant and disk have to have opposite facing velocities in the frame of the table.
IMAGE
But wouldn't this mean that both the ant and disk have a clockwise angular momentum around the CM of the entire system, meaning that there is a total clockwise angular momentum even though it was originally zero, violating conservation of angular momentum?

In their solution, I'm confused how they got equation (0-3).

0 replies

Riptide1901

May 26, 2025

0 replies

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Physics Paradox

Riptide1901 10

N May 26, 2025 by whoosh

Two identical small masses each of mass $m$ are connected by a light inextensible string on a smooth horizontal floor. A constant force $F$ is applied at the mid point of the string as shown in figure. Find the acceleration of each mass towards each other. The string is originally strait and taught.

I'm confused of a paradox that seems to emerge. When you apply the force, $F=ma$ implies that there should be a net acceleration of the CM of the system in the direction of the force. But at the same time, the tension can only apply forces on each mass towards one another (perpendicular to the direction of the force). So how is it possible that the CM of the masses accelerate in the direction of the force?

10 replies

Riptide1901

May 22, 2025

whoosh

May 26, 2025

J

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Applying momentum conservation

ARYANMATHS 8

N May 25, 2025 by whoosh

I am not to figure out whats exactly happening ..plz help me out

8 replies

ARYANMATHS

Sep 25, 2020

whoosh

May 25, 2025

J

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2015 F=MA Problem 2

millburnmathfan 2

N May 25, 2025 by millburnmathfan

I just tried to solve F=MA 2015 problem 2, and I had some doubts. For reference, the problem is:

A car travels directly north on a straight highway at a constant speed of 80 km/hr for a distance
of 25 km. The car then continues directly north at a constant speed of 50 km/hr for a distance of
75 more kilometers. The average speed of the car for the entire journey is closest to
(A) 55.2 km/hr
(B) 57.5 km/hr
(C) 65 km/hr
(D) 69.6 km/hr
(E) 72.5 km/hr

My solution was that the car traveled total 100 kilometers and it traveled at 80 km/hr for 25% of the journey while it traveled at 50 km/hr for 75% of the journey. In this case couldn't one just take the weighted average and do 0.25x80+0.75x50? Here, 0.25x80+0.75x50 gives us 57.5, which is answer choice B. However, the correct answer to this problem was A (55.2 km/hr). Can someone explain to me how to solve this problem and where did I go wrong in my solution?

Thanks

2 replies

millburnmathfan

May 25, 2025

millburnmathfan

May 25, 2025

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A Little Help Needed

Saucepan_man02 4

N May 25, 2025 by whoosh

I was going through this handout link. In Idea 5 of Section, I didnt quiet get what the statement meant. It was mentioned that it was proved in M2 handout (or Griffiths Problem 1.62), but I didnt quiet "get" the concept from either.

Could anyone kindly explain (it will be very helpful if the explanation is comprehensive and detailed) the "Idea 5" of the handout?
Thanks in advance...!

4 replies