- #1

Northbysouth

- 249

- 2

## Homework Statement

Points A and B are the midpoints of the sides of the rectangle. Replace the force F acting at A by a force-couple system at B. Give the general result and then answer for the specific case: F = 250 N, h = 185 mm, b = 490 mm. The couple is positive if counterclockwise, negative if clockwise.

## Homework Equations

## The Attempt at a Solution

I found R to be:

R = 250cos(37.065) + 250sin(37.0565)

R = 199.51i + 160.651j

I know my R is correct but I can't get the M

_{B}right.

If I draw a straight line connecting A and B, I find the angle at A in this triangle to be 20.6841 by using arctan.

At this point I have

M

_{B}= 250N*261.88cos(360-20.6841) + 250N*261.88sin(360-20.6841)

M

_{B}= -38.1249

It's negative because the force would clockwise. I've think I tried this answer previously and it was wrong. Does the y component go through the point B, thereby making it's value 0?