The moment of inertia of a body about a given axis is `1.2 kg m^(2)`. Initially, the body is at rest. In order to produce a rotational `KE` of `1500 j`, for how much duration, an acceleration of `25 rad s^(-2)` must be applied about that axis ?

Explanation

Here, `I = 1.2 kg m^(2), omega_(0) = 0`,
`alpha = 25 rad s^(-2), t = ?`
Additional rotational `K.E. = 1500 J`
`(1)/(2) I omega^(2) - (1)/(2)I omega_(0)^(2) = 1500`
As `omega_(0) = 0, (1)/(2)I omega^(2) = 1500`
`omega = sqrt((3000)/(I)) = sqrt((3000)/(1.2)) = 50 rad s^(-1)`
From `omega = omega_(0) + alpha t`
`50 = 0 + 25t, t = (50)/(25) = 2 s`