Tagged as: Exam, explanation, inertia, kinematics, Need, rotational, Studying
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by Doc_Smith on December 31, 2009
Tagged as: Exam, explanation, inertia, kinematics, Need, rotational, Studying
Previous post: Songwriting Tips For Writing Lyrics
Next post: College Life Season2 Ep7- “Change”

{ 1 comment… read it below or add one }
I don’t know…let’s see
Ke= 0.5Iw^2
I1= I2
w1=w2
so why would it it be different? Unless…
the moment of inertia for a sphere
I (sphere)=Is= (2/5) m R^2
and
I(disk)= Id= (1/2) m R^2
The total kinetic energy = Ke( traslational) +Ke(rotational)
Ke( translational) =(1/2)mV^2
since V=wR and
m(sphere)= (5/2) I /R^2
m(disk)= 2 I /R^2
Ke(translational) =(1/2)m (wR)^2
Ke(translational sphere) =[(1/2)(5/2) I /R^2](wR)^2=
Ke(translational sphere) =(5/4) I /(w)^2=
Ke(translational disk) =[(1/2)(2) I /R^2]wR)^2
Ke(translational disk) = I /(w)^2
Ke(translational sphere)/Ker(translational disk)= =(5/4) I /(w)^2 / I /(w)^2= 5/4
The linear kinetic energy will be larger for a sphere.