# Homework Help: Vectors and Forces

1. Jun 22, 2010

1. The problem statement, all variables and given/known data

If θ=30 degrees find the direction and magnitude of the resultant of these forces.
[PLAIN]http://img194.imageshack.us/img194/7899/image2iw.jpg [Broken]

2. Relevant equations

3. The attempt at a solution

Ok, so I know I have to add both of the vectors. I need to find the coordinates to do so. The first vector's coordinates must be <220,0>. Next I need to find the second vector's coordinates:

x=150cos30
x=[150√(3)]/2
y=150cos30
y=75

so the second vector has the coordinates <[150√(3)]/2,75>

If you add the second and the first vectors you get <[590√(3)]/2,75>

Then I found the magnitude of this new vector to be 590.63 newtons. However, this is wrong because the book's answer section says the magnitude should be 357.85 newtons.

If i go on to find the direction that also turns out wrong. What am I doing wrong?

Last edited by a moderator: May 4, 2017
2. Jun 22, 2010

### Staff: Mentor

The x-component of your vector sum is 590*sqrt(3)/2, which is about 510. That is incorrect, and is too large (you should get about 350). Take a look again at your calculation for this component.

3. Jun 22, 2010

Ahh. Thanks, I found my error. The x component should be:

[440+150√(3)]/2