Component vectors

1. Nov 26, 2009

lovemake1

Hello, im slightly confused with component vectors.

if im trying to add two vectors, which are 33m/s [W33E] and 53m/s [N54W] i have to
break them down in to x and y component.
i can get them by using cos and sin.

but there are some occasions where im not sure if the degree im using is correct.

for example for 33m/s the xcomponent would be 33cos33 and ycompoent would be 33sin33.

when do we ever use 33cos-33 ? beacuse i know there are some occasions where negative angle is neccesary or even (180-33) obtuse angle to find the component.

please could anyone clarify this for me thanks,

2. Nov 26, 2009

mikeph

I don't understand your notation [W33E]... are they something to do with the compass points?

3. Nov 26, 2009

h4tt3n

To add two or more vectors, just add their x and y components respectively. Simple as that. Your notation seems odd, though.

4. Nov 26, 2009

Staff: Mentor

Your [W33E] notation is incorrect. The other heading, [N54W], means 54 degrees west of north. The first one should probably be either N33E or S33E.

5. Nov 26, 2009

LCKurtz

Draw the vector with its tail at the origin. Then draw a polar coordinate angle from the positive x axis to the vector. It doesn't matter whether you go counterclockwise with a positive $\theta$ or clockwise with a negative $\theta$. Do whichever seems more natural for the vector you are considering. In either case you will get $x = r\cos\theta,\ y = r\sin\theta$.