Door Rotation: The Influence of Attached Rods and Forces

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Discussion Overview

The discussion revolves around the mechanics of door rotation when a rod is attached to it and a force is applied. Participants explore the implications of torque, the necessity of diagrams for clarity, and practical considerations regarding the experiment's execution.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • One participant suggests that attaching a rod to a door and applying force would cause the door to rotate due to the torque generated, as the force is not aligned with the hinge.
  • Another participant questions whether the original question simplifies to the broader question of whether a door can be opened.
  • Several participants emphasize the need for a diagram to accurately address the mechanics involved.
  • One participant proposes an absurdity extension technique to visualize the problem, suggesting that lengthening the rod could clarify the mechanics involved.
  • There are discussions about practical methods to conduct the experiment, including using clamps instead of nails, with some participants sharing their experiences and resources.
  • Another participant points out that if the door has handles, one could simply push on the handle to achieve the desired rotation without needing a rod.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of a diagram and the practicality of the experiment. While some agree on the mechanics of torque, there is no consensus on the best approach to explore the question or the implications of the setup.

Contextual Notes

Participants mention various assumptions regarding the setup, such as the door's design and the nature of the force applied. The discussion also reflects cultural differences in available tools and methods for conducting the experiment.

Who May Find This Useful

This discussion may be of interest to those exploring basic mechanics, torque, and practical applications of physics in everyday scenarios, as well as individuals curious about experimental methods in physics.

Erunanethiel
If I were to put attach a long rod to the side of a door (the exact opposite of the side where it is hinged, the slim part)

And then I apply a force to the the right side of the rod I attached, would the door rotate to the right, or would the hinge completely oppose the force and the door wouldn't move?
 
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It would rotate, as the force is not directly in line with the hinge, producing torque on the door.
 
Attaching a rod to a door is a reasonable model of "taking hold of the door handle". So doesn't this question boil down to "can I open a door", or am I misunderstanding something?
 
Last edited:
It's not possible to answer the original question without a diagram.
 
CWatters said:
It's not possible to answer the original question without a diagram.
I am on mobile, do you have any suggestions on how I can draw the diagram and upload it here?
 
Draw one on paper, take a good photo, upload it?
 
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CWatters said:
Draw one on paper, take a good photo, upload it?
Screenshot_20170926-051543.png
 
The door will rotate anticlockwise.
 
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Erunanethiel said:
do you have any suggestions on how I can draw the diagram and upload it here?
Wouldn't it have been simpler to find a door and try it?
 
  • #10
A.T. said:
Wouldn't it have been simpler to find a door and try it?
It would, but I like my doors enough to not hammer a nail to hold a rod in them
 
  • #11
Erunanethiel said:
It would, but I like my doors enough to not hammer a nail to hold a rod in them
And they have no handles sticking out?
 
  • #12
A useful trick in general is to imagine extending a situation to the point of absurdity. Imagine lengthening the rod until it's ten miles long. Then you've got something that looks very like a rod on a fulcrum, and your question becomes "can I tip a rod about a fulcrum?" Hopefully the answer is obvious.
 
  • #15
Erunanethiel said:
I am not in USA, all we have here is nails
They do not glue boards together in wherever-istan? Possibly I am about to be educated in how things are done elsewhere.
 
  • #16
jbriggs444 said:
They do not glue boards together in wherever-istan? Possibly I am about to be educated in how things are done elsewhere.
The main reason I didn't do it is it would take a lot of explaining to my family and can't do it without looking at least a little crazy of a person
 
  • #17
Erunanethiel said:
The main reason I didn't do it is it would take a lot of explaining to my family and can't do it without looking at least a little crazy of a person
My father once asked me a rhetorical question about whether it was better to be thought "normal" by one's peers or to live your own life. He lived his own life well.
 
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  • #18
Erunanethiel said:
The main reason I didn't do it is it would take a lot of explaining to my family and can't do it without looking at least a little crazy of a person

You don't need a rod, if the door has handles. Just push on the handle the way you indicated in your diagram. The door will rotate if the line of action of the force doesn't pass through the hinge axis.

figure_72.jpg
 
  • #19
jbriggs444 said:
My father once asked me a rhetorical question about whether it was better to be thought "normal" by one's peers or to live your own life. He lived his own life well.
Bless him
 

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