35. A uniform solid sphere of mass M and radius R rotates with an angular speed ω about an axis through its center. A uniform solid cylinder of mass M, radius R, and length 2R rotates through an axis running through the central axis of the cylinder. What must be the angular speed of the cylinder so it will have the same rotational kinetic energy as the sphere?
(A) 2ω/5
(B) 2ω/ 5eeae3c5f03a7.jpg
(C) ω/ 5eeae3e5d7276.jpg
(D) 5eeae3f61900d.jpgω
(E) 4ω/5

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統計： A(1), B(41), C(0), D(5), E(5) #2356596

詳解 (共 2 筆)

#4426231
考細心... 要看清楚, 2R為圓柱高度...
(共 108 字，隱藏中）
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#4744585
solid sphere:I=2/5mR^2
Solid cylinder:I=1/2mR^2
rotational kinetic energy相同 I x w^2 =const.
2/5 x w^2 =1/2 x wc ^2
wc = 2/√5 w
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