## Sample problems

Below is a set of problems to demonstrate the level of the contest. Most problems from the list below have appeared before and are presented here only as an example, the actual olympiad will consist of fully original problems. The final set of problems will appear in the personal team page exactly at the start of the contest.

#### Two balls

Landau's theoretical exam, classical mechanics

Two balls (with masses m and M) are positioned along one line which is perpendicular to the massive wall. The right ball moves to the left with velocity v (in the direction of the wall). Find the sum N1 + N2, where N1 is the total number of collision between the left ball and the wall and N2 is the total number of collisions between the balls.

#### Metallic cavity

Textbook problem

Find the force acting on a positive charge e located at an arbitrary point in a cubic cavity (with edge b) of a metallic medium.

#### Free falling charge

The problem is recent and still scientic.

A charge e with mass m is in a free fall in the gravitational field of Schwarzschild black hole. For a static observer it moves with an acceleration. Would it be radiating according to the observer?

#### Hydrogen atom

Textbook problem

Let us consider H atom in a weak uniform magnetic field. Assume that an electron is in the ground state and that the motion of a proton is adiabatically slow with respect to the electron. Find an effective Hamiltonian describing the motion of the proton under these conditions and show that it behaves as a particle of zero charge.