Register to reply 
Determine the angle between the force and the line 
Share this thread: 
#1
Feb1010, 01:10 AM

P: 190

1. The problem statement, all variables and given/known data
Just have to determine the angle between the force and the line "OC". 2. Relevant equations [tex]\vec{P}[/tex] [tex]\bullet[/tex] [tex]\vec{Q}=PQcos(\alpha)[/tex] ?? 3. The attempt at a solution I tried using different triangles to find the angle but couldn't come up with one. I "moved" the 12X24 box down the xaxis so OC starts from the tail of the vector. Am I supposed to use F_{xy} some way? Thanks for your help, I've been working on this for a couple hours now.. 


#2
Feb1010, 07:47 AM

Sci Advisor
HW Helper
Thanks
P: 26,148

Hi frozenguy!
Forget triangles, use coordinates … what are the coordinates of the vectors AB and OC ? 


#3
Feb1010, 11:22 AM

P: 190

Thanks for taking a look! Ok, so for AB, the coordinates are (12,0,0), (0,24,8) OC=> (0,0,0), (12,24,0) Then I can say that the components of the lines are AB: <12,24,8> OC:<12,24,0> Doting all of those gets me 432, and the product [tex]\leftAB\right[/tex][tex]\leftOC\right=751[/tex] Therefore, [tex]\theta=cos^{1}(\frac{432}{751})[/tex] or, [tex]\theta=54.96[/tex] which is what the answer says! Is this what you were referring to when you mentioned coordinates? Also, this probably is really elementary, but what is the relation between coordinates and forces? Because sometimes that 200lb would be considered the length of the hypotenuse, but it's really only 28 in this case. Thanks again for your help, Frozenguy 


Register to reply 
Related Discussions  
Find the point of intersection of the plane and line. Determine if line lies in plane  Calculus & Beyond Homework  5  
Determine angle of force  Introductory Physics Homework  6  
Determine point on line where normal passes thr a point intersects the line.  Calculus & Beyond Homework  7  
Determine angle for gun to be shot at  Introductory Physics Homework  2  
Determine the values of a and c on a line.  Calculus & Beyond Homework  3 