2. A record is dropped vertically onto a freely rotating turntable (kinetic energy of the record is negligible). Frictional forces act to bring the record and turntable to a common angular speed. If the rotational inertia of the record is 0.66 times that of the turntable, what percentage of the initial kinetic energy is lost?
(A) 40%
(B) 34%
(C) 56%
(D) 66%
(E) 19%
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統計: 尚無統計資料
統計: 尚無統計資料