Kinetic energy of rotation of a flywheel of radius 2 m , mass 8 kg and angular speed 4 rad s - 1 about an…

Kinetic energy of rotation of a flywheel of radius 2 m, mass 8 kg and angular speed 4 rad s-1 about an axis perpendicular to its plane and passing through its center is
  1. 128 J
  2. 196 J
  3. 256 J
  4. 392 J

Solution

Given that
Mass of wheel \(m=8 \mathrm{~kg}\) radius \(r=2 \mathrm{~m}\)
Angular speed \(\omega=4 \mathrm{rad} \mathrm{s}^{-1}\)
Rotational kinetic energy of wheel
$\begin{aligned} k & =\frac{1}{2} I \omega^{2} \\ & \Rightarrow k=\frac{1}{2} \frac{m r^{2}}{2} \omega^{2} \\ & \Rightarrow k=\frac{1}{2} \frac{8 \times 4}{2} 4^{2}=128 \mathrm{~J} \end{aligned}$

Asked in: JEE Mains - Rotational Motion - Test 3

Practice more Rotational Motion questions on Aicharya