Rotational kinetic energy problem

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Homework Help Overview

The problem involves a solid sphere with specified mass and radius that is both sliding and spinning. The context centers around calculating the rotational kinetic energy based on given translational kinetic energy proportions.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to find the rotational kinetic energy using the moment of inertia and angular velocity, while also noting the proportion of kinetic energy in translational motion. Some participants suggest ensuring all relevant kinetic energy equations are included, particularly for translational motion.

Discussion Status

The discussion is ongoing, with participants providing guidance on including necessary equations. There is an emphasis on careful reading of the problem statement to ensure all aspects are considered.

Contextual Notes

Participants are navigating the relationship between translational and rotational kinetic energy, with specific attention to the proportions given in the problem. There may be assumptions about the completeness of the provided equations that are being questioned.

blackbyron
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Homework Statement


A solid sphere with a mass 8.2kg and radius 10cm is sliding along a frictionless surface with a speed 5.4m/s while at the same time spinning. The sphere has 0.31 of its total kinetic energy in translational motion. How fast is the sphere spinning?


Homework Equations



KAe = (1/2)(I)(W)^2


The Attempt at a Solution



The problem is that the rotational kinetic energy is unknown, but I found that the inertia is .0328kgm^2

How do I find the rotation kinetic energy so I can solve for w?
 
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In the relevant equations, you have left out the formula for calculating the kinetic energy due to translation of the sphere at the given speed.
 
SteamKing said:
In the relevant equations, you have left out the formula for calculating the kinetic energy due to translation of the sphere at the given speed.

You mean this ?

Translation:

Ke = (1/2)(m)(v^2)
 
Ya. Now reread your problem statement very carefully.
 

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