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An object with an unknown moment of inertia rolls (without slipping), starting f

ID: 1782961 • Letter: A

Question

An object with an unknown moment of inertia rolls (without slipping), starting from rest, down an incline. Which choice correctly relates the initial gravitational potential energy PEi, the final translational kinetic energy KEftrans, and the final rotational kinetic energy KEfrot? (Assume there is just enough friction to keep the object rolling, but ignore energy loss to friction.)

A) PEi < (KEftrans + KEfrot)

B) PEi = KEitrans = KEfrot

C) PEi + KEfrot = KEftrans

D) PEi = KEftrans > KEfrot

E) PEi > KEftrans and PEi > KEfrot

Explanation / Answer

In view of Conservation of Energy, P.E.i should be equal to K.E.ftrans + K.E.fRot

therefore Answer (E) Since P.E. will be higher than both K.E. trans and K.E.Rot seperately