Component vectors

**lovemake1** · Nov26-09, 01:41 PM

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,

**MikeyW** · Nov26-09, 01:59 PM

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

**h4tt3n** · Nov26-09, 02:02 PM

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

**Mark44** · Nov26-09, 04:20 PM

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.

**LCKurtz** · Nov26-09, 11:03 PM

Originally Posted by lovemake1

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,

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 $LaTeX Code: \\theta$ or clockwise with a negative $LaTeX Code: \\theta$ . Do whichever seems more natural for the vector you are considering. In either case you will get $LaTeX Code: x = r\\cos\\theta,\\ y = r\\sin\\theta$ .