Weight distribution of 2 configurations

In summary, the conversation revolves around the weight distribution along the bottom edge of Rectangle-B in Figure-1 and Figure-2. The weight distribution is not uniform in Figure-1 and the question is whether it will be the same in Figure-2. The conversation also touches on the concepts of moments, free body diagrams, and sum of forces. The goal is for the individual to figure out the answer themselves, but they are unable to do so and decide to leave the forum.
  • #1
member 534986
TV Weight distribution 02b 500h.jpg


Say Object-A weighs 100 lbs.
In Figure-1, it's obvious that the weight distribution is even along the bottom edge of Rectangle-B.

In Figure-2, ignoring the weight of the white objects, is the weight distribution exactly the same along the bottom edge of Rectangle-B as it is in Figure-1?
 
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  • #2
What do you think, and why? Are you familiar with how to draw Free Body Diagrams (FBDs) and sum forces and moments?
 
  • #3
HRG said:
Summary:: Weight distribution

View attachment 253509

Say Object-A weighs 100 lbs.
In Figure-1, it's obvious that the weight distribution is even along the bottom edge of Rectangle-B.

In Figure-2, ignoring the weight of the white objects, is the weight distribution exactly the same along the bottom edge of Rectangle-B as it is in Figure-1?
Hint: The moments around the center of mass must balance in both cases.
 
  • #4
berkeman said:
What do you think, and why? Are you familiar with how to draw Free Body Diagrams (FBDs) and sum forces and moments?
Nope. I'm just a curious senior. This is not a homework problem.
 
  • #5
A.T. said:
Hint: The moments around the center of mass must balance in both cases.
You totally lost me. I'm just a curious senior hoping for an explanation from the gurus.
 
  • #6
HRG said:
You totally lost me. I'm just a curious senior hoping for an explanation from the gurus.
It's good to be curious. Google "sum of moments" and "free body diagram".

Senior in high school? :smile:
 
  • #7
berkeman said:
It's good to be curious. Google "sum of moments" and "free body diagram".

Senior in high school? :smile:
Nope, senior as in 79 years old.
 
  • #8
HRG said:
Nope, senior as in 79 years old.
Ah, got it, LOL.

What is your math background? It doesn't take advanced math to work out a sum of moments (a moment is basically a torque, multiplying the force by the lever arm length, and ratioed to the angle that the force is applied at the end of the lever arm).

Here is a basic article about FBDs:

https://en.wikipedia.org/wiki/Free_body_diagram

And here are the Google search results for Sum of Moments:

https://www.google.com/search?q=sum...VCMH0KHXDbAcMQ_AUIDCgA&biw=1206&bih=564&dpr=1

which includes a couple instruction videos on how to apply the sum of moments to solve a statics problem like the one you have asked about. :smile:
 
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  • #9
HRG said:
Summary:: Weight distribution

View attachment 253509

Say Object-A weighs 100 lbs.
In Figure-1, it's obvious that the weight distribution is even along the bottom edge of Rectangle-B.
This is not correct. The force distribution along the bottom edge of rectangle B in Figure 1 is not uniform. It is higher toward the center than towards the edges.

Have you ever had a course in calculus? If you are talking about the force distribution along the bottom edge, are you comfortable with the idea that the force distribution is described by the local value of the upward force per unit width?
 
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  • #10
Chestermiller said:
This is not correct. The force distribution along the bottom edge of rectangle B in Figure 1 is not uniform. It is higher toward the center than towards the edges.

Have you ever had a course in calculus? If you are talking about the force distribution along the bottom edge, are you comfortable with the idea that the force distribution is described by the local value of the upward force per unit width?
Let me reword my statement.

"In Figure-1, if 2 small blocks of wood are placed underneath Rectangle-B, one flush with the left edge and the other flush with the right edge, then the weight pressing on each block would be identical assuming the load is directly in the center of Rectangle-B."

Will the same condition exist in Figure-2?
 
  • #11
HRG said:
Will the same condition exist in Figure-2?
What do you think and why? (Have you actuially been reading the links and hints we have been giving you? )
 
  • #12
Yes, I googled the suggestions but could not figure out the answer to my question. That's OK. I didn't come here for a physics lesson. I should have known better having read replies to questions from other people. I just hoped for an answer but it's like pulling teeth.

I understand that gurus here don't want to give answers. Only to guide people to figuring out the answers for themselves. No problem with that. It's just not my goal at 79 years.

Bye physicsforum. There's no point in my returning.
 
  • #13
HRG said:
I understand that gurus here don't want to give answers. Only to guide people to figuring out the answers for themselves. No problem with that. It's just not my goal at 79 years.
Thanks for the complement. That is indeed what we try to do. Best wishes.
 
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  • #14
BTW, I think I asked a couple times what you think about the problem, but I don't think you replied to that. I know what I think intuitively and with just basic visualization of what would happen, but I'd need to do the FBDs and calculations to be sure.

Can you say what you feel intuitively would happen (before you leave us)? Thanks.
 

Related to Weight distribution of 2 configurations

What is weight distribution?

Weight distribution refers to the way in which the weight of an object or system is distributed among its different components or parts. It is an important concept in engineering and physics, as it can greatly affect the stability and performance of a structure or machine.

How is weight distribution measured?

Weight distribution is typically measured by calculating the center of mass of an object or system. This is done by finding the average position of all the individual weights and their distances from a reference point. The center of mass can then be used to determine the distribution of weight in different configurations.

What factors can affect weight distribution?

There are several factors that can affect weight distribution, including the shape and size of an object, the materials it is made of, and any external forces acting on it. Additionally, the placement and arrangement of components within an object can also impact its weight distribution.

Why is weight distribution important in engineering?

Weight distribution is important in engineering because it can greatly impact the stability, strength, and performance of structures and machines. By understanding and optimizing weight distribution, engineers can design more efficient and effective systems that can better withstand external forces and stresses.

How can weight distribution be optimized?

Weight distribution can be optimized by carefully considering the design and placement of components within an object or system. This can involve redistributing weight to achieve a more balanced and stable configuration, or using materials with different densities to achieve a desired weight distribution. Computer simulations and physical testing can also be used to fine-tune weight distribution in engineering designs.

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