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

Answer:

t=62 s

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:

$F_g=m.g\\\\m=\frac{706N}{9.81}\\\\m=72.0kg$

now:

$m*v_{f1}=-m_b*v_b\\\\V_{f1}=-\frac{m_b*v_b}{m}\\\\V_{f1}=-\frac{1.2kg*8.0m/s}{72.0kg}\\\\V_f=-0.13m/s$

That is 0.13m/s due south.

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

$d=v*t\\t=\frac{d}{v}\\t=\frac{8m}{0.13m/s}\\\\t=62s$