Problem
A 720 N student stands in the middle of a frozen pond having a radius of 5.086 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 3.452 kg physics textbook horizontally toward the north shore at a speed of 6.4 m/s. The acceleration of gravity is 9.81 m/s^2. How long does it take him to reach the south shore?