Question

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?

Answer 1

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

Step-by-step 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

`x_(B,G) = x`

`x_(A,G) = x_(A,B) + x_(B,G)`

= 2.9 + x

`x_(B,G) = x_(B,Boat) + x_(B,G)`

= -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.