A Vector + Trig Problem

[SaiNight]

The problem is attached.
I think the cosine rule needs to be used to solve this problem, but I can't seem to find enough information to be able to do so.

 

[Dr.Peterson]

I think the cosine rule needs to be used to solve this problem, but I can't seem to find enough information to be able to do so.

You've got the right idea to start with; we need to fill in the gaps. The first thing to do is to sketch each situation. Have you done that?

For the first part, it would look something like this:

[FONT=courier new]                 B
       V    /  /
        /    /100
    /      /
O-------->A
    500[/FONT]

Does that agree with your understanding of the situation?

How might you use the law of cosines to find the length (speed) V? How can you then find the direction?

In order to help you best, we need to see as much of your own thinking as possible, not just the general fact (good as it is) that you recognize the usefulness of the law of cosines. Please show your work for the rest of this part, as far as you can get, and then show us your sketch of the second part (either the way I did, or as a photo).