• Support PF! Buy your school textbooks, materials and every day products Here!

Finding the x and y components of this vector

  • Thread starter kevnm67
  • Start date
  • #1
43
0
Hey guys,

I am not sure I did this problem correctly and would like some feedback. Below is how I reasoned through the problem. Thanks for your help.

Kevin


Homework Statement



Find x- and y-components of the vector (3.0 , - x-direction).


Homework Equations


cosθ= A/H
sinθ= O/H

H= -3.0

The Attempt at a Solution



I made two vectors connecting to form a 90 degree angle pointing at the hypotenuse. The other two angles are now 45 degrees and I plugged them in to the above equations as follows:
cos(45)=A/-3 = -2.12
sin (45)=O/-3= -2.12

(-2.12)^2 + (-2.12)^2 = -3^2
8.99 or 9 = 9
So X and Y are both -2.12
 

Answers and Replies

  • #2
lewando
Homework Helper
Gold Member
1,349
135
Am I correct in reading that your original vector looks like this:

3 <----------------+

?

If so, I dont see much of a y-component.
 
  • #3
43
0
Am I correct in reading that your original vector looks like this:

3 <----------------+

?

If so, I dont see much of a y-component.
yes. But isn't that the resultant vector? I solved two other prior to this question and they gave a magnitude and direction. To solve those, I made two vectors and solved for their side of the triangle. Is that not how I should be trying to solve this question? At first I thought it would be 0, but it's not, at least to my understanding, asking for the x and y coordinates of the line drawn above
 
  • #4
lewando
Homework Helper
Gold Member
1,349
135
This problem is a special case where the direction lies exactly along one of the axes, in which case there is no right triangle for you to construct. So your trig functions don't apply.
 
  • #5
43
0
This problem is a special case where the direction lies exactly along one of the axes, in which case there is no right triangle for you to construct. So your trig functions don't apply.
So does that mean x= -3 and y=0?
 
  • #6
lewando
Homework Helper
Gold Member
1,349
135
That sounds right to me! Good luck with your coursework.
 
  • #7
43
0
That sounds right to me! Good luck with your coursework.
Thanks for your help!
 

Related Threads on Finding the x and y components of this vector

Replies
7
Views
2K
Replies
4
Views
11K
Replies
4
Views
22K
Replies
2
Views
2K
Replies
4
Views
839
  • Last Post
Replies
2
Views
1K
Replies
4
Views
5K
Replies
2
Views
6K
  • Last Post
Replies
9
Views
5K
Top