# Homework Help: Momentum of 15 ton train

1. Nov 12, 2007

### KatieLynn

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

What speed must a 15 metric ton train travel to have a momentum of 700,000 kg(m/s)?

2. Relevant equations

Momentum = mass X velocity

change in momentum = mass(Finalvelocity - initialvelocity)

3. The attempt at a solution

I though you did it like this...

15 metric tons= 15,000 kg

so 700,000=15,000V

V=46.6 m/s

2. Nov 12, 2007

### Kurdt

Staff Emeritus
That looks ok to me. Except if you report the answer to one decimal place you'll have to round it up.

3. Nov 12, 2007

### KatieLynn

Well see thats the problem, my teacher is having us enter our answers on to a university of Texas homework service site thing. So to help us not enter all wrong answers and get a horrible grade, he gave us a "range" for the answers of each problem, for that problem it says the answer is "a small positive integer 1-10"

4. Nov 12, 2007

### Kurdt

Staff Emeritus
Well the only thing i can suggest is that there is a typo somewhere. I assume you've checked the units it has to be entered in and everything.