A wheel of mass 8 kg and radius 40 cm is rolling on a horizontal road with angular velocity 15 rad/s. If moment of inertia of the wheel about its axis is `0.64 kg m^(2)`, then the rolling kinetic energy of wheel will be

Options

A. 288 J
B. 216 J
C. 72 J
D. 144 J

Answer

B

Explanation

Here, `m=8kg, r=40cm=(2)/(5)m,`
`omega=12"rad s"^(-1), l=0.64 kg-m^(2)`
`"Total KE"=(1)/(2)l omega^(2)+(1)/(2)mv^(2)=(1)/(2)l omega^(2)+(1)/(2)mr^(2)omega^(2)`
`=(1)/(2)xx0.64xx15^(2)+(1)/(2)xx8xx((2)/(5))^(2)xx15^(2)=216J`