A 776 N student stands in the middle of a frozen pond having a radius of 4.2 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 2.7 kg physics textbook horizontally toward the north shore at a speed of 5.3 m/s. How long does it take him to reach the south shore?

Question

cwrw238 · Answer

i think you can do this using conservation of momentum 
the students momentum will equal that of of the book
so we have 
776 * v = 2.7 * 9.8 * 5.3
v = (2.7*9.8 *5.5) / 776  m / s

then you can find the time taken