# Rotational Motion: Rotational vs. translational kinetic energy

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

## Answers and Replies

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Drakkith
Staff Emeritus
Science Advisor
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.

Drakkith
Staff Emeritus
Science Advisor
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