Two people, one of mass 78 kg and the other of mass 59 kg, sit in a rowboat of mass 88 kg. With the boat initially at rest, the two people, who have been sitting at opposite ends of the boat 2.9 m apart from each other, now exchange seats.How far will the boat move?

Respuesta :

The boat will move -0.24 m and the negative sign indicates left direction.

Explanation:

mass of people A = 78 kg

mass of people B = 59 kg

mass of rowboat = 88 kg

Let the displacement of the boat be x

                               [tex]x_{B,G} = x[/tex]

                               [tex]x_{A,G} = x_{A,B} + x_{B,G}[/tex]

                                        = 2.9 + x

                               [tex]x_{B,G} = x_{B,Boat} + x_{B,G}[/tex]

                                        = -2.9 + x

As net external F = 0

                                ∑mx = 0

        88 (x) + 78 (2.9 + x ) + 59 (-2.9 + x) = 0

          88x + 226.2 + 78x - 171.1 + 59x = 0

         225x + 55.1 = 0

                           x = -55.1 / 225

                          x = -0.24

The negative sign indicates left direction.