# Momentum/Impulse problem

1. Jun 17, 2012

### anthonych414

1. The problem statement, all variables and given/known data

A 45.0-kg woman stads up in a 60-kg canoe 5.00 m long. She walks from a point 1.00 m from one end to a point 1.00 m from the other end. If you ignore resistance to motion of the canoe in water, how far does the canoe move during this process.

2. Relevant equations

p=mv
J=p2-p1
p1=p2

3. The attempt at a solution

I guess I should try to make the momentum before and after equal, but I don't know how to relate that to the distance.

2. Jun 17, 2012

### Infinitum

Since there is no external force acting on the system in the direction of motion, you can use the fact that the position of center of mass remains unchanged. Draw out a diagram, and frame equations making sure that the COM stays same.

3. Jun 17, 2012

### tiny-tim

hi anthonych414!

hint: what happens to the centre of mass?

4. Jun 17, 2012

### anthonych414

Right, the center of mass! I can't believe I didn't think of it! I feel silly... Anyway thanks for the help guys :D