Door Rotation: The Influence of Attached Rods and Forces

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SUMMARY

The discussion centers on the mechanics of door rotation when a force is applied to a rod attached to the door. It is established that the door will rotate if the force applied is not in line with the hinge, thereby creating torque. The conversation also touches on practical methods for simulating this scenario, such as using clamps instead of nails. Participants emphasize the importance of visual aids, like diagrams, to better understand the mechanics involved.

PREREQUISITES
  • Understanding of basic physics concepts such as torque and force.
  • Familiarity with mechanical systems, specifically door mechanics.
  • Knowledge of tools such as clamps for practical experimentation.
  • Ability to create and interpret diagrams for mechanical scenarios.
NEXT STEPS
  • Research the principles of torque and how it applies to levers and hinges.
  • Learn about different types of clamps and their applications in mechanical setups.
  • Explore methods for creating accurate diagrams to represent mechanical forces.
  • Investigate practical experiments to demonstrate the effects of force on door rotation.
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Physics students, mechanical engineers, DIY enthusiasts, and anyone interested in understanding the mechanics of door operation and force application.

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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