The document is solving a physics problem about a father's distance from a telephone located in the center of a 3.4 meter diameter circle. It uses trigonometric functions to model the father's circular motion and determines that the time when he was 2.4 meters from the phone was 0.9976 seconds. Given this time and the radius of 1.7 meters, the arc length between the father and phone when it rang is calculated to be 1.6959 meters.