# Homework Help: Net force and Newton's laws of motion

1. Sep 19, 2011

### warrior2014

Net force and Newton's laws of motion!!!

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

A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 490 N at an angle of 19° with the centerline of the canal. What is the net force on the barge?

2. Relevant equations

Fx= F1x + F2x.....
Fy= F1y + F2y....
Fnet

3. The attempt at a solution

I broke it into components and got the following:

F1x= 490cos19
F2x=490cos19
F1y=490sin19
F2y=490sin19

I'm not too sure where to go from here. I think you add all the Fx components and Fy components, then square them and take the square root but when I tried that, I got it wrong, which was 980 N (and they do not give you the correct answer).

Any help will be appreciated!!

2. Sep 19, 2011

### Dick

Re: Net force and Newton's laws of motion!!!

You have to consider direction of the force as well as magnitude. Do F1y and F2y point in the same direction??

3. Sep 19, 2011

### warrior2014

Re: Net force and Newton's laws of motion!!!

F1y points upwards and F2y points downwards. So then when you do the sum of Fy=0. Then I tried to find Fnet and got 30.44 N which is also incorrect. I don't know what I am doing wrong :S

4. Sep 19, 2011

### Dick

Re: Net force and Newton's laws of motion!!!

Yes, the y forces cancel. But how you did you get 30.44N?? Just giving an answer makes it hard to guess what you did wrong.

5. Sep 19, 2011

### warrior2014

Re: Net force and Newton's laws of motion!!!

since F1x= 490cos19 and F2x= 490cos19, I added them and got 926.61 so I squared this answer and then did the square root of it. what am I supposed to do exactly and why?

6. Sep 19, 2011

### warrior2014

Re: Net force and Newton's laws of motion!!!

oh never mind. HUGE calculation error on my part. I got the correct answer :) thanks for your help!!