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 rotational kinetic energy of 1500 J, an angular acceleration of 25 rad/s² must be applied about an axis for a time duration of (a) 8 s (b) 2 s (c) 4 s (d) 1 s

Answer: (b). 1/2Iω² = 1500 ⇒ ω² = (3000)/(1.2) = 2500, ω = 50 rad/s From rest: t = (ω)/(α) = 50/25 = 2 s So the answer is (b) 2 s.

The moment of inertia of a body about a given axis is 1.2 kg m²… | MHT CET 2021 (21 Sep, Shift 1)

Q39MHT CET 2021 · 21 SEP · SHIFT 1Medium

Rotational Kinetic Energy, Work & Power

The moment of inertia of a body about a given axis is $1.2\text{ kg m}^{2}$ . Initially the body is at rest. In order to produce rotational kinetic energy of $1500\text{ J}$ , an angular acceleration of $25\text{ rad/s}^{2}$ must be applied about an axis for a time duration of

Show answer and solution

Answer: (b)

$\frac{1}{2}I\omega^2 = 1500 \Rightarrow \omega^2 = \frac{3000}{1.2} = 2500$ , $\omega = 50$ rad/s
From rest: $t = \frac{\omega}{\alpha} = \frac{50}{25} = 2$ s
So the answer is (b) 2 s.

Report a mistake

Rotational Kinetic Energy, Work & Power question from MHT CET 2021 (21 Sep, Shift 1)

More questions on Rotational Kinetic Energy, Work & Power