A 730.0 N man, carrying a 1.9 kg physics textbook, stands at the center of a frozen pond of radius 10.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome his difficulty, he throws his textbook horizontally at a speed of 5.0 m/s toward the north shore. How long (in s) does it take him to reach the south shore?