Thread: velocity components

Originally Posted by willowthewisp

I posted one question already this morning and I have just one more I need help with:

"A current is flowin at 1 m/s in the direction 30 degrees east of due north. what are the velocity components in the (a) east direction and (b) north direction?"

the answers given are: a= 1* cos60 = .5 and b= 1* sin60 = .86

what I can't understand is why the answers use 60 instead of the 30 degrees stated in the question???

the illustration accompanying this problem looked like a right angle with the current closer to the y axis so 90-30 is 60 but I still don't know why 60 is used and not 30/

thanks for any help

It's because when dealing with a co-ordinate system, the angles are measured in the anticlockwise direction of the positive x axis.

thanks a lot!