A 715 N man stands in the middle 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 this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore at a speed of 10.0 m/s. How long does it take him to reach the south shore?

Question

A 715 N man stands in the middle 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 this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore at a speed of 10.0 m/s. How long does it take him to reach the south shore?

Damon · Answer

first find his mass in kilograms
m = 715 / 9.81

then use conservation of momentum
(total of 0 before the toss)
0 = (715/9.81) v - 1.2 * 10

solve for v
how long does it take to go 10 meters at v meters/second?