Question 268: Centre of Mass and Rotational Motion

Question

Moment of inertia of a body about a given axis
is 1.5 kg m2. Initially the body is at rest. In order
to produce a rotational kinetic energy of
1200 J, the angular accleration of 20 rad/s2
must be applied about the axis for a
duration of :-

Accepted Answer

KE = $${1 \over 2}I{\omega ^2} = 1200$$ (given)
$$ \Rightarrow \omega  = 40\,rad/s$$
$$ \Rightarrow \omega  = {\omega _0} + \alpha t$$
$$ \Rightarrow 40 = 0 + (20)t$$
$$ \Rightarrow t = 2\,\sec $$

Answer

2.5 s

Answer

3 s

Answer

5s

Answer

2 s

Centre of Mass and Rotational Motion

Moment of inertia of a body about a given axis is 1.5 kg m2. Initially the body is at rest. In order to produce a rotational kinetic energy of 1200 J, the angular accleration of 20 rad/s2 must be applied about the axis for a duration of :-

Choose the correct answer: