- #1
chetzread
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Homework Statement
why the force of distributed act upward?
Homework Equations
The Attempt at a Solution
why shouldn't it act downward due to gravity pull?
Understanding Distributed Load Forces: Causes and Effects on Objects
- Thread starter chetzread
- Start date
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Discussion Overview
The discussion revolves around the nature of distributed loads and their directional effects on objects, particularly in the context of structural engineering. Participants explore the implications of load direction on equations and assumptions related to gravity and other forces.
Discussion Character
- Homework-related
- Conceptual clarification
- Debate/contested
Main Points Raised
- Some participants question why the force of a distributed load acts upward rather than downward, given the influence of gravity.
- Others note that the textbook may depict loads acting in their positive direction, which could explain the upward force representation.
- A participant suggests that if the load were to act downward, maintaining consistent sign conventions would not alter the equations derived.
- There is a proposal that the distributed load could represent a scenario where gravity is not the only force considered, such as a window mullion experiencing wind load.
- One participant challenges the assumption that the distributed load acts vertically, suggesting it might be horizontal based on the diagram's perspective, which could enhance understanding of practical applications in engineering.
Areas of Agreement / Disagreement
Participants express differing views on the direction of distributed loads and the assumptions underlying the problem. There is no consensus on whether the load should be considered vertical or horizontal, nor on the implications of these assumptions for calculations.
Contextual Notes
Participants highlight the importance of sign conventions and the context of the load application, indicating that assumptions about load direction may affect interpretations but not necessarily the mathematical outcomes.
Who May Find This Useful
This discussion may be useful for students and practitioners in engineering and physics who are exploring the concepts of distributed loads and their effects in structural analysis.
why the force of distributed act upward?
why shouldn't it act downward due to gravity pull?
- #2
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
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If you read the text in the book, the author has chosen to show the loads acting in their positive direction. which is why F is pointing up rather than down, like a gravity load.chetzread said:Homework Statement
why the force of distributed act upward?
Homework Equations
The Attempt at a Solution
why shouldn't it act downward due to gravity pull?
- #3
Delta2
Homework Helper
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What do you think would change in the equations if you take the load to act downwards?
As long as you keep stable the sign conventions through the whole derivation, nothing changes in the equations.
As long as you keep stable the sign conventions through the whole derivation, nothing changes in the equations.
Last edited:
- #4
pongo38
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You may be assuming that the distributed load is against gravity. This problem could be a model of a structural member such as a window mullion carrying a distributed wind load, where gravity is a force along the axis of the member.
- #5
chetzread
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Do you mean the author assume the beam carrying win load , so the forces act upwards?pongo38 said:
- #6
pongo38
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I don't know what the author assumed. I am just indicating that you have made an assumption that the distributed load is acting vertically, when it might just be acting horizontally if you regard the diagram (a) given as a plan., rather than as an elevation. All this doesn't affect the calculations, but helps you understand a possible application of the mechanics that does occur in everyday engineering practice.
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