Question

if an object's rotational kinetic energy is 64 j and it rotates with an angular speed of 9 radians/s, what is its moment of inertia?

Answer 1

• Kinetic Energy=K.E=64J
• Angular Speed=$\omega$=9rad/s
• Moment of Inertia=I

$\\ \sf\longmapsto K.E=\dfrac{1}{2}I\omega^2$

$\\ \sf\longmapsto 64=\dfrac{1}{2}I(9)^2$

$\\ \sf\longmapsto 81I=128$

$\\ \sf\longmapsto I=\dfrac{128}{81}$

$\\ \sf\longmapsto I=1.5kgm^2$