As solid sphere of mass ' M ' and radius ' R ' spins about an axis passing through its…

As solid sphere of mass ' M ' and radius ' R ' spins about an axis passing through its centre making 600 rpm. Its kinetic energy of rotation is
  1. 2π25MR
  2. 2π5M2R2
  3. 80πMR
  4. 80π2MR2

Solution

Rotational kinetic energy, K.E=12Iω2

⇒K.E=12×25MR2×600×2π602

⇒K.E=15MR2×20π2

⇒K.E=15MR2×400π2

⇒K.E=80π2MR2

Asked in: AP EAMCET 2021 (20 Aug Shift 2)

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