Replace Loading on Frame By Single Resultant (HW Help)

In summary, the task is to find the intersection point of the resultant's line of action with member BC, measured from point B. The given forces are F1 = 250 lb and F2 = 90 lb, with a moment of 500 lb*ft. The correct answer is x = 2.34, but the attempt resulted in x = -2.34. This is due to a negative moment value obtained from the sum of moments of the two forces, which was treated as negative in the calculation.
  • #1
lc99
161
3

Homework Statement



upload_2018-2-16_22-25-11.png

upload_2018-2-16_22-25-25.png

Q) Suppose that F1 = 250 lb , F2 = 90 lb , and M = 500 lb⋅ft . (Figure 1) Specify where the resultant’s line of action intersects member BC, measured from B.

Homework Equations

The Attempt at a Solution


Okay, so i am having severe problems with figuring out what i did wrong...
I am given : F1 = 250 and F2 = 90. The correct Force result is = 245 i +228 j with magnitude of 335 .
The moment given is 500 lb*ft.

I am trying to find the result's line of action that would intersect member BC measured from B. The correct answer is x = 2.34.

But, i got some other answer. I found the location of intersection with M = Fy * x (Fy because Fx would be 0 along the x-axis).

so , 500 = 228*x --> x = 2.19?? Which is wrong :(
 

Attachments

  • upload_2018-2-16_22-25-11.png
    upload_2018-2-16_22-25-11.png
    9.6 KB · Views: 2,162
  • upload_2018-2-16_22-25-25.png
    upload_2018-2-16_22-25-25.png
    14.2 KB · Views: 2,018
Physics news on Phys.org
  • #2
Actually , guys, i understand what i did wrong. I had to find the sum of moments from also the forces given. I get the sum of moments from the two forces as -1033 n*m. However, the value is negative? Nevertheless, when i summed -1033 with 500 , i get -533 n*m. So, M = fy*d --> d = -533/228 = -2.34.

I got the correct answer except the value i get is negative? Is this suppose to happen or was i suppose to treat clockwise motion as Positive?
 

1. How does replacing loading on frame by single resultant work?

Replacing loading on frame by single resultant involves calculating the net forces acting on a frame and finding a single resultant force that has the same effect as all the individual forces combined. This simplifies the analysis of the frame and makes it easier to determine its overall stability and strength.

2. What are the benefits of replacing loading on frame by single resultant?

Replacing loading on frame by single resultant can save time and effort in analyzing the stability and strength of a frame. It also allows for a more accurate understanding of the forces acting on the frame and can help in identifying potential weak points or areas of failure.

3. Can replacing loading on frame by single resultant be used for all types of frame structures?

Yes, replacing loading on frame by single resultant can be used for all types of frame structures, including trusses, beams, and frames with multiple supports. However, the method may be more complex for frames with non-uniform loading or complex geometries.

4. How do you find the single resultant force when replacing loading on frame?

To find the single resultant force, you must first determine the net forces acting on the frame, including external forces, internal forces, and reactions at supports. Then, you can use vector addition to find the resultant force, which will have the same magnitude and direction as the net forces acting on the frame.

5. Are there any limitations to replacing loading on frame by single resultant?

While replacing loading on frame by single resultant can simplify the analysis of a frame, it does have limitations. It assumes that all forces are acting in the same plane and ignores the effects of moments or distributed loads. It is also important to ensure that the resultant force is applied at the correct location on the frame to accurately represent the original loading.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
2
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
3K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
25K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
15K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
15
Views
5K
  • Engineering and Comp Sci Homework Help
Replies
8
Views
8K
Back
Top