Question

And 84.1 kg man is standing on a frictionless ice surface when he throws a 1.80 kg book at 11.1 m/s. With what velocity does the man move across the ice

Answer 1

Final velocity of man is -0.23 m/s.

Explanation:

Conservation of linear momentum :

When no external force acts on a  system of several interacting particles, the total linear momentum of system is conserved.

Before the Throw ; Man mass (M₁) = 84.1 kg,

                                Velocity of Man (u₁) = 0 m/s

                                Book Mass(M₂) = 1.80 kg

                                 Velocity of book (u₂)= 0 m/s

 After the throw ;   Man mass(M₁) = 84.1 kg

                                Velocity of Man(V₁) = ?

                                 Book mass(M₂) = 1.80 kg

                                  velocity of book(V₂) = 11.1 m/s

  According to conservation of linear Momentum

    Initial Momentum = Final Momentum

 M₁u₁ +M₂u₂ =  M₁v₁ + M₂v₂

84.1 x0 + 1.80 x0 = 84.1 x v₁ + 1.80 x 11.1

   0         =     84.1 v₁  + 19.98

v₁ =   -19.98 /84.1

     = -0.23 m/s

final velocity of man is -0.23 m/s