Why does the 30Ns vector get flipped in the Two Dimensional Impulse Problem?

[rusty711]

Homework Statement

an object with a mass of 5.0 kg is moving 4.0m/s north when an impulse of 30Ns 45 deg N of W is applied to it. what is its new velocity?

Homework Equations

The Attempt at a Solution

I understand the process until solving for the angle. Why does the 30Ns vector get flipped?[/B]

 

[haruspex]

I understand the process until solving for the angle. Why does the 30Ns vector get flipped?

We can't tell what's puzzling you unless you post the actual steps in the working and indicate what you consider to be the flip.

 

[rusty711]

We can't tell what's puzzling you unless you post the actual steps in the working and indicate what you consider to be the flip.

I drew the two vectors how they were given and solved for the resultant and the angle using cos law and sine law. But, in the answer key, the 30Ns vector was drawn reversed resulting in a different angle. Why is this?

 

[haruspex]

I drew the two vectors how they were given and solved for the resultant and the angle using cos law and sine law. But, in the answer key, the 30Ns vector was drawn reversed resulting in a different angle. Why is this?

I still can't tell whether it is you or the answer key that has it backwards. Can you describe in words how you interpreted the given direction?