# Physics

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A solid disk rolls along the floor with a constant linear speed v.

(a) Find the fraction of its total kinetic energy that is in the form of rotational kinetic energy about the center of the ball.

Krot/Ktotal = ?

• Physics -

Total KE=rotaionalKE + linearKE
= 1/2 momentInertia*(v^2/r^2) + 1/2 mass*v^2

• Physics -

The rotational KE is
(K.E.)rot = (1/2) I w^2
The angular velocity is w = V/R
The moment of inertia is (1/2) M R^2 for a solif disc.

Express (K.E.)rot in terms of M and V.

Then calculate
(K.E.)rot/[(1/2 M V^2 + (K.E.)rot]

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