- #1
QuarkCharmer
- 1,051
- 3
Homework Statement
Homework Equations
The Attempt at a Solution
Well, I have the whole thing drawn out, and calculated some information that will be needed.
[itex]|A|=7.92[/itex]
[itex]|B|=8.28[/itex]
I am assuming that the question means that vector C is perpendicular with vector A, meaning, there is 90 degrees between them.
a.) Find the x component of C
It says that the scalar product of C and B is 13, so I am guessing that means I have to know the angle between those two vectors. Which would be the angle between B and A minus 90 degrees right?
How do I find the angle between B and A ?
Alright, so:
[tex]A\bullet B = (4.8)(-3.9)+(-6.3)(7.3)[/tex]
[tex]A\bullet B = -64.71[/tex]
and since [itex]A\bullet B = |A||B|cos(\theta)[/itex]
[tex]|A||B|cos(\theta) = -64.71[/tex]
[tex]cos(\theta) = \frac{-64.71}{(7.92)(8.28)}[/tex]
[tex]\theta = 170.67 degrees[/tex]
Then the angle between B and C is 80.67 degrees, which looks about right.
So then, the scalar/dot product of C and B is:
[tex]C \bullet B = |8.28||C|cos(80.67) = 13[/tex]
[tex]|C| = \frac{13}{cos(80.67)|8.28|}[/tex]
[tex]|C| = 9.68[/tex]Now what?
I don't see how the components of C are coming out of this.
Last edited: