# Vector prblem, HELP ME

1. Jul 8, 2004

### schrodingersequation

A jogger travels a route that has two parts. The first is a displacement A of 2.50 km due south, and the second involoves a displacement B that points due east. (a) The resultant displacement A+B has a magnitude of 3.75 km. What is the magnitude of B, and what is the direction of A+B relative to due south? (b) suppose that A-B had a magnitude of 3.75 km. What then would be the magnitude of B, and what is the direction of A-B realtive to due south?
:uhh:

I have an answer for this problem I just want to know if it is right.
(a)The magnitude of B is 2.80 km
A+B points 48.188 degrees East of South

(b)the magnitude of B is 2.80 km
A-B points 48.188 degrees West of South

Last edited: Jul 8, 2004
2. Jul 8, 2004

### AKG

Looks pretty good. In finding the direction, I got the angle to be 48.190. Make sure you're not using rounded values, in fact you can just use cosX = 2.50/3.75, and solve for X (which is what I did). However, you should round to 3 significant digits, giving you 48.2 anyways, which would be the same using my number or yours.