1.

A body having a moment of inertia about its axis of rotation equal to 3 "kg-m"^(3) is rotating with angular velocity of 3 "rad s^(-1). Kinetic energy of this rotating body is same as that of a body of mass 27 kg moving with a velocity v. The value of v is

Answer»

`1 ms^(-1)`
`0.5 ms^(-1)`
`2 ms^(-1)`
`1.5 ms^(-1)`

Solution :We know that the kinetic energy, `K = (1)/(2)mv^(2)=(1)/(2)I omega^(2)`
where, `m = 27 kg` (mass of the BODY)
`omega = 3 "rads"^(-1)` (angular VELOCITY)
`I = 3 "kg-m"^(2)` (moment of INERTIA)
`v = ? or mv^(2)=I omega^(2)`
`rArr v^(2)=(I omega^(2))/(m)rArrv^(2)=(3xx3^(2))/(27)rArrv^(2)=(27)/(27)=1`
`rArr` Velocity of body, `v = sqrt(1) = 1 ms^(-1)`.


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