Question

A body of moment of inertia of 3 kg-m² rotating with an angular velocity of 2 rad/sec has the same kinetic energy as a mass of 12 kg moving with a velocity of

• A. 8 m/s
• B. 0.5 m/s
• C. 2 m/s
• D. 1 m/s

Answer 1

Answer: (D)

1 m/s

Answer 2

Rotational kinetic energy of the body = $\frac{1}{2}I\omega^{2}$and translatory kinetic energy $= \frac{1}{2}mv^{2}$

According to problem $= \frac{1}{2}I\omega^{2} = \frac{1}{2}mv^{2}$

⇒ $\frac{1}{2} \times 3 \times (2)^{2} = \frac{1}{2} \times 12 \times v^{2}$⇒ $v = 1m ⥂ / ⥂ s$.