Replace all the loads on the beam with one resultant force.

In summary, the problem is to determine the resultant of the loads acting on a beam with a given distance of 1.5m, as well as the point of application of this resultant on the beam. The given data includes F1=100KN, l1=1m, F2=50kN, l2=1.5m, and F3=60KN, l3=4m. Using the equation R=F1+F2-F3=90KN (pointing downwards), it is found that the resultant force R is pointing downwards at 90KN and is located 0.722m from the left end of the beam. However, there may be a discrepancy in the solution due to the location
  • #1
aerograce
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1

Homework Statement



Knowing the distance d=1.5m, determine the resultant of the loads acting on the beam shown in the attachment. Specify the point of application of this resultant on the beam.

Given data: F1=100KN, l1=1m. F2=50kN,l2=1.5m. F3=60KN, l3=4m.
Variables: Resultant Force R, and its lever arm L.

Homework Equations



R=F1+F2-F3=90KN(Pointing downwards)
Take the most left point as reference:
M=-F1*l1-F2*l2+F3*l3=65 KN*m (Counterclockwise direction)

The Attempt at a Solution


The problem I have is that, since R is pointing downwards, it will never create a counterclockwise direction moment, hence this problem cannot be solved. But on my book, anwser is given like this:
R=90KN downwards @0.722m from the left end

Thank you for helping me:)
 

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  • #2
You have the 50 kN load located at 4m from the left end. This location does not match the attached diagram.
 
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  • #3
SteamKing said:
You have the 50 kN load located at 4m from the left end. This location does not match the attached diagram.

Sorry for my mistake, corrected just now
 

1. What is the purpose of replacing all the loads on the beam with one resultant force?

The purpose of replacing all the loads on the beam with one resultant force is to simplify the analysis of the beam. It allows for the calculation of the overall effect of all the loads on the beam in one step, rather than individually calculating the effects of each load.

2. How is the resultant force calculated?

The resultant force is calculated by summing all the individual forces acting on the beam and finding the vector sum. This can be done using mathematical equations or by constructing a force diagram.

3. What are the benefits of using a resultant force?

Using a resultant force allows for a quicker and more efficient analysis of the beam. It also simplifies the calculations and reduces the chances of errors. Additionally, it provides a clearer understanding of the overall effect of the loads on the beam.

4. Are there any limitations to using a resultant force?

One limitation of using a resultant force is that it assumes all the loads act on the beam at the same point. This may not always be the case in real-world scenarios, and therefore, the results may not be entirely accurate. Additionally, using a resultant force does not take into account the distribution of forces along the beam.

5. Can a resultant force be used for all types of beams?

Yes, a resultant force can be used for all types of beams, including simple beams, cantilever beams, and continuous beams. However, for more complex beams with varying cross-sections or loads, the calculation of the resultant force may be more challenging and may require more advanced techniques.

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