229 Y-coordinate of the point of application of the force

Problem 229
In Fig. P-229, find the y-coordinate of point A so that the 361-lb force will have a clockwise moment of 400 ft-lb about O. Also determine the X and Y intercepts of the line of action of the force.

Point of application of a force


Solution 229



How did you get 2/Sqrt13 as the dimension in y direction?

You have to break down the Force F into its components: Fx and Fy. Arrow F has a 2:3 slope ( count the number of squares). Its hypotenuse by P-theorem is the square root of 13. To resolve Fy you have to multiply F with 2/square root of 13. Hope this helps.

The slope appears to be 2:3, but that information is not provided in the problem statement or the diagram, so the solution uses an unjustified assumption.

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