A spherical solid ball of 1 kg mass and radius 3 cm is rotating about an axis passing through its centre with an angular velocity of 50 rad `s^(-1)`. The kinetic energy of rotation is

Options

A. 450 J
B. 45 J
C. 90 J
D. 0.45 J

Answer

D

Explanation

`E=(1)/(2)lomega^(2)=(1)/(2)xx((2)/(5)mr^(2))omega^(2)=(1)/(5)mr^(2)omega^(2)`
`=(1)/(5)xx1xx(3xx10^(-2))^(2)xx50^(2)=0.45J`