- #1
pucr
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Homework Statement
A solid sphere has a mass of 1.0 kg. It is rolling at a translational speed of 10 m/s. What is the total energy of the rolling sphere?
I think I got the problem but I'm not sure I went about it the right way.
Homework Equations
I = (2/5)mr^2
KE_rot = (1/2)Iw^2
KE = (1/2)mv^2
The Attempt at a Solution
I assumed KE_total = KE_rot + KE...which I'm not sure is right.
So...
KE_rot = (1/2)Iw^2 = (1/2)(2/5)(m)(r^2)(w^2) = 20 Joules
and...
KE = (1/2)(m)(v^2) = 50 Joules
soo...
KE_total = 70 Joules
This is the right answer, but I'm not sure if the total kinetic energy is actually the rotational kinetic energy plus the linear kinetic energy. Also...what is translational velocity? Is this any different than the sphere moving in a direction?