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The moment of inertia of a body about a given axis is 1.2 kg m². Initially, the body is at rest. In order to produce a rotational kinetic energy of 1500 joule, an angular acceleration of 25 radian/sec² must be applied about that axis for a duration of
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- 4 seconds
- 2 seconds
- 8 seconds
- 10 seconds
Correct Option: B
I = 1.2 kg m², Er = 1500 J,
α = 25 rad/sec², ω1 = 0, t = ?
| As Er = | Iω², ω = √ | |||
| 2 | I |
| = √ | = 50 rad/sec | |
| 1.2 |
From ω2 = ω1 + αt
50 = 0 + 25 t, t = 2 seconds
