I have a problem for HW that is driving me crazy!(adsbygoogle = window.adsbygoogle || []).push({});

A copy of the original problem from the text is attached.

Here is what I have done so far...

First, I split the area under the force horizontally into two triangles and found the centroid of each.

Centroid of upper triangle is 3m from left side.

Centroid of lower tri is 6 m from left side.

Area force of triangle 1 is 15.75 kN

Area force of triangle 2 is 6.75 kN

Total area force is 22.5 kN

Location to place this equivalent force is 3.9m from left side.

I believe I am good to this point. Now, to find the reactions at point B and C, I have setup the following equations:

Sum Fy = By + Cy - 22.5kN - 50kNm/2m - 50kNm/8m = 0

and

Sum Ma = 2m*By + 8m*Cy - 22.5kN(3.9m) - 50kNm = 0

Solving these equations simultaneously I end up with

Cy = 5.04kN

By = 48.71kN

According to the answers in the back of the book (Vector Mechanics for Engineers, 7th ed - Beer, Johnston & Eisenberg) the answers are

Cy = 15.46 kN

By = 7.04 kN

Any help would be greatly appreciated. I am spent on this problem and just cannot see where I am going wrong. I suspect my problem is how I am dealing with the 50kNm torque shown on the diagram.

Thanks.

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# Homework Help: Mechanic Statics Problem

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