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 KE of 1500 J , the angular acceleration of 25 rad s- 2 must be applied about that axis for a duration of

Question

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 KE of 1500 J , the angular acceleration of 25 rad s- 2 must be applied about that axis for a duration of (A) 4 s (B) 2s (C) 8s (D) 10s

Tardigrade Admin · Accepted Answer

I=1.2 kg m2 ω i=0 ; α =25 rad s- 2 Rotational KE =(1/2)IÏf2=1500J ⇒ ω f=50rads- 1 ⇒ t=(ω f - ω i/α )=(50/25)=2s

Q. The moment of inertia of a body about a given axis is $1.2 k g m^{2}$ . Initially, the body is at rest. In order to produce a rotational KE of $1500 J$ , the angular acceleration of $25 r a d s^{- 2}$ must be applied about that axis for a duration of

$4 s$

$2 s$

$8 s$

$10 s$

$I = 1.2 k g m^{2}$
$ω_{i} = 0$ ; $α = 25 r a d s^{- 2}$
Rotational KE $= \frac{1}{2} I ω_{f}^{2} = 1500 J$
$\Rightarrow ω_{f} = 50 r a d s^{- 1}$
$\Rightarrow t = \frac{ω _{f} - ω _{i}}{α} = \frac{50}{25} = 2 s$

Q. The moment of inertia of a body about a given axis is 1.2kgm2 . Initially, the body is at rest. In order to produce a rotational KE of 1500J , the angular acceleration of 25rads−2 must be applied about that axis for a duration of

4s

2s

8s

10s