Finding the magnitude of the moment on a pipe wrench

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

A force of 56 pounds acts on the pipe wrench shown.
find the magnitude of the moment about O by evaluating || OA x F ||

2. Relevant equations

|| OA x F ||

3. The attempt at a solution

First I tried to find my vector component for Force which I got
-56 [ cos(30)i + sin(30)j ]

Since my force on wrench is 56 pounds and it is in a downward vertical I used F=-56
To which my vector for F simplified to =
-28sqrt(3)i -28j

Now I needed to find a component vector from O to A.
Which I initially thought would be
0i+0j +(3/2)k
Since 3/2 ft (18in) is how long my wrench is?

after I get my two vector components I use the cross product and find the magnitude. I just needed some guidance on my vectors for F and vector(OA)
Attachment 66855.

http://ift.tt/1f1RyUx

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