Rotational motion energy

[kaspis245]

Homework Statement

Same mass sphere and cylinder are rolling on a horizontal plane. Which part of each objects kinetic energy does objects rotational energy make up?

Homework Equations

E_rotational = 1/2 Iw²

E_kinetic = 1/2 mv²

The Attempt at a Solution

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I know, that moments of inertia are:

I_cylinder = 1/2 MR²

I_sphere = 2/5 MR²

And I know that:

E_total = E_k + E_rotational

What sould I do?

 

[Doc Al]

What sould I do?

For rolling without slipping, how are $\omega$ and $v$ related?

 

[kaspis245]

Well, v = wR .

 

[Doc Al]

Well, v = wR .

Exactly. Use that to relate rotational and translational kinetic energy.