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

Physic Vector Problem

  • Thread starter Paymemoney
  • Start date
  • #1
175
0

Homework Statement


Find the components of the vector [tex]\vec{C}[/tex] with length c = 1.00 and angle [tex]\phi = 30.0^{\circ}[/tex] as shown.

NV_ct.jpg

Homework Equations


[tex]opp=hypcos(\theta)[/tex]
[tex]adj=hypcos(\theta)[/tex]


The Attempt at a Solution



tried to use the above equations to answer the question, however when i looked in the answers it was incorrect.
Answer i got was x=0.866 and y=0.5

When i realized that it was between the vector and the y axis, i found that the angle didn't make contact with the x-axis, so my question is What is the angle that [tex]\vec{C}[/tex] makes with the positive x axis?

P.S
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
25,832
249
Hi Paymemoney! :smile:

Homework Equations


[tex]opp=hypcos(\theta)[/tex]
[tex]adj=hypcos(\theta)[/tex]
erm :redface: … they can't both be right, can they? :biggrin:
When i realized that it was between the vector and the y axis, i found that the angle didn't make contact with the x-axis, so my question is What is the angle that [tex]\vec{C}[/tex] makes with the positive x axis?
Start at the positive x-axis, go round to the y-axis, then go round some more … that's your angle! :wink:

But the main thing you've done wrong is that the dotted line marked "x" on your diagram isn't x, is it? :smile:
 
  • #3
175
0
Hi Paymemoney! :smile:


erm :redface: … they can't both be right, can they? :biggrin:
oops, meant to be [tex]opp=hypsin(\theta)[/tex]

Start at the positive x-axis, go round to the y-axis, then go round some more … that's your angle! :wink:

But the main thing you've done wrong is that the dotted line marked "x" on your diagram isn't x, is it? :smile:
ok so i got 600 degrees, what is the next step i should take to solve [tex]\vec{C}[/tex]
 
  • #4
tiny-tim
Science Advisor
Homework Helper
25,832
249
Hi Paymemoney! :smile:

(have a degree: º and a theta: θ and a phi: φ :wink:)
ok so i got 600 degrees …
hold it!

however did you get 600º ? :confused:
 
  • #5
175
0
well i went around the the axis 2 times o_o
 
  • #6
tiny-tim
Science Advisor
Homework Helper
25,832
249
well i went around the the axis 2 times o_o
Still not 600º. :confused:

Anyway, just go from the x-axis to the y-axis anticlockwise, and then carry on to C.
 
  • #7
175
0
ok this is what i have done:

vectorquess.JPG

tell me if this is correct.
 
  • #8
tiny-tim
Science Advisor
Homework Helper
25,832
249
Yes, that's exactly correct. :smile:

The "first quadrant" (top-right) is 0º to 90º, the "second quadrant" (top-left) is 90º to 180º, and so on. :wink:
 
Top