Question

A 706-N man stands in the middle of a frozen pond of radius 8.0 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 8.0 m/s. How long does it take him to reach the south shore?

Answer 1

t=62 s

Step-by-step explanation:

Applying the conservation of linear momentum formula:

`(m1+m2)*v_(o1)=m1*v_(f1)+m2*v_(f2)`

the initial velocity is zero, we can calculate the man's mass using the gravitational force formula:

`F_g=m.g\\\\m=(706N)/(9.81)\\\\m=72.0kg`

now:

`m*v_(f1)=-m_b*v_b\\\\V_(f1)=-(m_b*v_b)/(m)\\\\V_(f1)=-(1.2kg*8.0m/s)/(72.0kg)\\\\V_f=-0.13m/s`

That is 0.13m/s due south.

because there is no friction, the man will maintain a constant velocity, so:

`d=v*t\\t=(d)/(v)\\t=(8m)/(0.13m/s)\\\\t=62s`