Question

Ok, I think I have this...mostly. A dog, weighing 10.0lbs, is standing on a flatboat so that he is 20.0 ft from the shore. He walks 8.00 ft on the boat toward shore and then halts. The boat weighs 40.0 lbs. Assume no friction between boat and water. How far is the dog from the shore? Does the center of mass of the dog+boat move? (I'll add what I've done in a moment).

Answer 1

The center of mass doesn't move. My final answer is that the dog is 14ft from shore when he stops. The book gets 13.6. I did this with \[(m_1+m_2)V = m_1v_1 + m_2v_1\] I figured that the time it took didn't matter, and so assumed -8ft/s for the dog and solved for the velocity of the boat.

Answer 2

I should mention that I got *exactly* 14m, so I don't think it was a rounding error.