MathDB
Revolutions the astronaut performs

Source: Baltic Way 1995

October 8, 2011
geometry proposedgeometry

Problem Statement

The following construction is used for training astronauts: A circle C2C_2 of radius 2R2R rolls along the inside of another, fixed circle C1C_1 of radius nRnR, where nn is an integer greater than 22. The astronaut is fastened to a third circle C3C_3 of radius RR which rolls along the inside of circle C2C_2 in such a way that the touching point of the circles C2C_2 and C3C_3 remains at maximum distance from the touching point of the circles C1C_1 and C2C_2 at all times. How many revolutions (relative to the ground) does the astronaut perform together with the circle C3C_3 while the circle C2C_2 completes one full lap around the inside of circle C1C_1?