# Need help with this homeowork

1. Oct 4, 2013

### damdamct

1. The problem statement, all variables and given/known data
Vector A has a magnitude of 9.10 and is directed at 55.0 degrees. Vector B has a magnitude of 12.5 and is directed at 125 degrees . The x component of vector C is 8.60. The vectors are related by the equation A-2B=pC, where p Is a scalar. Find the value of p , the y component of C and the magnitude and the direction of vector C

2. Relevant equations
x component = Acos(O)
y component = Asin(O)
magnitude = squaroot of x^2 +y^2
direction =arctan(y/x)

3. The attempt at a solution
i tried to attempt on this problem and got
p=-1.06
Cy=-26.4
|C| = 27.8
C direction = 361.9 degrees, not sure if i am right

Last edited: Oct 5, 2013
2. Oct 4, 2013

### NewSoul

Ok. I think you need to break this up into steps. First, calculate the x-component for A and B. Then, use what you know to solve for p. After that, you can figure out the rest of C.

3. Oct 5, 2013

### damdamct

i tried to attempt on this problem and got
p=-1.06
Cy=-26.4
|C| = 27.8
C direction = 361.9 degrees, not sure if i am right

4. Oct 5, 2013

### SteamKing

Staff Emeritus
direction = square root of x^2 + y^2? Where did you get this equation?

Hint: what is the magnitude of a vector in terms of its components?

5. Oct 5, 2013

### damdamct

Oops , I am sorry , square root of x^2 + y^2 would be a formula of the magnitude . Direction = arctan(y/x).
Like i said , i have tried to attempt on this problem already and i got some answers on the #2 post above. I am not sure that if those are right the right answers or not. Can someone confirm the answers for me please?

6. Oct 5, 2013

### haruspex

It's a lot easier for those trying to help if you post all your working, purely symbolically, only substituting numbers at the end.

7. Oct 5, 2013

### damdamct

so here is what i got

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