United States Physics Olympics

The United States Physics Olympiad, or USAPHO, is comprised of 2 exams, the preliminary exam, or screening exam, and the semi-final exam. However, USAPHO is sometimes used to refer to just the semi-final exam, as it is the last of the national physics exams (and is thought of as analogous to USAMO).

Preliminary Exam

The preliminary exam is used to select approximately the top 200 high school physics students in the US that will go on the become US Physics Team semifinalists. Any high school student in the US is eligible to take this exam.

The test is a total of 100 minutes long, with a total of 140 possible points. It is composed of a 40 minute, 40 point multiple choice section, containing 20 questions worth 2 points each, followed by a 60 minute, 100 point free response section, containing 4 problems worth 25 points each. The multiple choice questions cover all topics included in AP Physics B, at a somewhat higher level, while all 4 free response questions are mechanics problems, with the easiest being at about the same level as the harder AP Physics C: Mechanics problems.

The tests are initially graded by the students' teachers themselves, then mailed in to be regraded. This initial grading is meant to help with the organization of the official grading.

Semi-final Exam

Approximately the top 200 scorers on the preliminary exam are invited to take the semi-final exam. The purpose of this exam is to select the members of the US Physics Team.

The Semi exam is a 2 part, 3 hour exam, with a total of 200 possible points, and is entirely composed of free response problems. Part A is 90 minutes long and contains 4 problems, worth 25 points each. These problems can cover any topic and are much more difficult than those on the free response section of the preliminary exam. Part B is also 90 minutes in length and contains 2 problems, worth 50 points each. These problems are longer and generally more difficult than those in part A, and can cover any topic.

The tests are the primary measure used to select the 24 members of the US Physics Team, but transcripts and letters of reccomendation are also taken into account. Once selected, the top 24 students are invited to attend a training camp in May, from which the top 5 students and 1 alternate are selected to compete in the International Physics Olympiad, or IPhO.

Sample Problems

Although the difficulty varies from year to year, both the preliminary and the semi-final exams from previous years can be found at [1].

However, the solutions have not been posted for any of the free response questions. This, according to the site, is to prevent students from doing well on similar problems by merely memorizing the previous solutions.