# Homework Help: HELP System of particles problem

1. Nov 8, 2008

### Kudo Shinichi

HELP!!!System of particles problem

1. The problem statement, all variables and given/known data
A 10kg dog walks 3m on a 20kg boat towards shore. How much nearer the shore does the dog end up if the boat was initially at rest.

3. The attempt at a solution
I am not really sure how to approach this problem. I think that the dog is 3 meters closer to the shore, because the boat stays at rest while the dog moves toward the shore...yet I think this is wrong because it is too simple as a physics problem...

Can anyone help me with this problem? thank you very much.

2. Nov 9, 2008

### jr01

Re: HELP!!!System of particles problem

hey, here's how i solved this question...not sure if its right. I think we're in the same class

Pi=Pf

m1v1=m2v2

v=d/t

(m2= 20kg + 10kg because the boat and the dog are the same mass once the dog stops moving)

10(3/t) = 30(d/t)

The t's then cross out

30=30d

d=30/30

d= 1.0m

Last edited: Nov 9, 2008