Can Torque Be Defined in Non-Rotational Situations?

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Discussion Overview

The discussion explores the definition and application of torque, particularly in non-rotational situations. Participants examine whether torque can be defined when forces are applied to objects that are not in rotational motion, considering both theoretical and practical implications.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant states the definition of torque as τ = r x F and questions whether torque can be defined using a distance from a point external to a rotating disk, suggesting that this could yield a different torque value compared to using the axis of rotation.
  • Another participant agrees that torque can be defined in non-rotational situations, noting that the definition does not inherently require rotation.
  • A different viewpoint suggests that defining torque in a non-rotational context is problematic, as torque is fundamentally linked to the generation of rotation when a force is applied.
  • One participant provides an example of using a wrench to turn a bolt, indicating that torque can be applied at a distance from the point of rotation, and discusses how varying the lever arm affects the torque produced.

Areas of Agreement / Disagreement

Participants express differing views on whether torque can be meaningfully defined in non-rotational contexts. While some assert that it can be defined, others argue that torque is inherently associated with rotational motion, leading to an unresolved debate.

Contextual Notes

Participants do not fully clarify the assumptions underlying their definitions of torque, nor do they resolve the implications of applying torque in non-rotational scenarios. The discussion reflects varying interpretations of the concept.

physics user1
The definition of torque is τ= r x F

Let's consider a disk that is rotating around his axis of symmetry, we are usually used to calculate the torque applied by a tangential force at the disk using as r the radius of the disk, but can I define a torque of the force using as r the generic distance between a point external of the disk? In this case will be the torque by this point different by the one referred to the axis of rotation? In my opinion yes because it's the most logical thing

Can we define a torque in a non rotation situation? Think at a particle that is pulled by a force in a uniform accelerated motion, according to the definition of torque we can choose a point in space and get the distance between that point and the force and get a torque, is that right?
 
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Cozma Alex said:
Can we define a torque in a non rotation situation?
Yes, the definition of torque says noting about rotation.
 
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Cozma Alex said:
Can we define a torque in a non rotation situation?

one can define a torque from taking radius vector from the axis and the force vector applied at a point on the body- as its a vector product the torque will generate a rotation due to application of the force. so you can not say that its a non rotational system.
 
Cozma Alex said:
The definition of torque is τ= r x F

... but can I define a torque of the force using as r the generic distance between a point external of the disk? In this case will be the torque by this point different by the one referred to the axis of rotation?
The answer to the first question is "yes" -- this is what happens every time a wrench is used to turn a bolt or a nut; the force is applied at some distance external to the bolt head or nut.
The answer to the second question is, "it depends" -- the same force (F) applied to a longer lever-arm (r) will yield a proportionally greater torque. Said another way, a longer lever-arm allows the same torque to be developed with proportionately less force.
 

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