Rotational Motion: Rotational vs. translational kinetic energy

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Discussion Overview

The discussion centers around the comparison of rotational and translational kinetic energy in the context of an inertia experiment. Participants explore the relationship between the two types of kinetic energy as observed in experimental trials with varying mass placements on a rotating apparatus.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant presents experimental data showing that the final rotational kinetic energy is significantly larger than the final translational kinetic energy in trials with different mass placements.
  • Another participant questions whether translational energy refers to the movement of an object in a straight line, such as left/right or up/down.
  • A participant defines translational kinetic energy as the kinetic energy associated with rectilinear motion, providing the formula 1/2*m*v^2.
  • Another participant suggests that the small amount of translational energy observed may be due to the center of mass wobbling, implying that most energy is rotational.

Areas of Agreement / Disagreement

Participants express differing views on the nature of translational kinetic energy and its relationship to rotational kinetic energy. There is no consensus on the reasons for the observed energy distribution in the experiments.

Contextual Notes

Participants do not fully explore the assumptions underlying their definitions and observations, nor do they clarify the conditions under which the energy measurements were taken.

Who May Find This Useful

Readers interested in the principles of rotational and translational motion, experimental physics, and the relationship between different forms of kinetic energy may find this discussion relevant.

adenine135
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In an inertia experiment using equipment very similar to the link below, I determined the following:

Trial with two 100 g masses near the ends of the rotating apparatus (larger moment arm):
- Final translational kinetic energy: 5.73 * 10^(-4) J
- Final rotational kinetic energy: 0.638 J

Trial with two 100 g masses closer in on the rotating apparatus (smaller moment arm):
- Final translational kinetic energy: 1.27 * 10^(-3) J
- Final rotational kinetic energy: 0.638 J

The final rotational kinetic energy is much larger than the final translational kinetic energy. Why is that the case?

http://www.usdidactic.com/images/produktbilder/04061000/Datenblatt/04061000 2.pdf
 
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Is translational energy the movement of an object other than rotating? IE left/right, up/down, ETC?
 
Translational kinetic energy is the kinetic energy associated with rectilinear motion, equal to 1/2*m*v^2.
 
adenine135 said:
Translational kinetic energy is the kinetic energy associated with rectilinear motion, equal to 1/2*m*v^2.

Looks to me like the you have very little translational energy because its all rotational energy. The small amount of translational energy is possible from the center of mass wobbling about?

Got my info from here: https://www.physicsforums.com/showthread.php?t=177052
 

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