What is this site? And who is Alferov? Read about it.

Latest problems
Center of Mass #12
Winnie-the-Pooh on the Ladder #11
Kettle and Bulb #10
Ladder at the Wall #9
Subway Train Acceleration #8
LED Strip Study #7
Light Emitting Diodes #6

Do you know you can set up similar website in 15 minutes? Check link at the bottom of the page!