Rotation Work Equation: Torque x Displacement = Rotational Equivalent

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Discussion Overview

The discussion centers on finding the rotational equivalent of the linear work equation, specifically exploring how torque and displacement relate to work in rotational dynamics. Participants are examining the appropriate substitutions for force and displacement in the context of rotational motion, as well as the associated units.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant proposes that torque should replace force in the work equation, questioning what the equivalent of displacement would be.
  • Another participant confirms that angles in radians are appropriate for the rotational equivalent.
  • A later reply suggests that the complete rotational work equation is work = torque * angle, noting that torque has dimensions of energy and that angles are dimensionless.
  • Another participant adds that for rotational problems, displacement can be expressed as the product of radius and angle, linking force and torque through this relationship.

Areas of Agreement / Disagreement

Participants generally agree on the substitution of torque for force and the use of angles in radians, but the discussion remains open regarding the complete formulation of the equation and the interpretation of displacement in rotational contexts.

Contextual Notes

There are unresolved aspects regarding the complete formulation of the rotational work equation and the definitions of displacement in this context, as well as the relationship between torque and energy dimensions.

24forChromium
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what would be the rotational equivalent of:

work = force * displacement

?

I assume that the force should be replaced with torque, but have no idea what the displacement should be replaced with, angles in radian? I'd appreciate it to see some units too.
 
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24forChromium said:
angles in radian?
Yes
 
A.T. said:
Yes
any ideas what the rest of the equation and its units look like?
 
24forChromium said:
any ideas what the rest of the equation and its units look like?
As A.T has pointed out, your first post has the complete answer: work = torque * angle
where torque has the same dimensions as work (i.e energy) given that angles are dimensionless. Units of torque: Joules or equivalently Newton * meters. Units of angle: radians.
 
The point is for rotational problems, your displacement is the radius * angle and force * radius is precisely the torque acting on a particle.
 
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