A solid sphere of mass M and radius R spins about an axis passing through its centre making 600 rpm. Its kinetic energy of rotation is

A solid sphere of mass M and radius R spins about an axis passing thro

1.	A solid sphere of mass M and radius R spins about an axis passing through its centre making 600 rpm. Its kinetic energy of rotation is
Answer» `(2)/(5) pi^2 MR` `(2)/(5) pi M^2 R^2` `80 pi MR` `80 pi^(2) MR^(2)` Solution :Kinetic energy of ROTATION , `K_(R) = (1)/(2) I omega^(2)` Here , `I= (2)/(5) MR^(2) , omega = (600 xx 2pi)/(60) = 20 pi` rad/s `therefore K_(R) = (1)/(2) xx (2)/(5) MR^(2) (20 pi)^(2) = 80 pi^(2) MR^(2)`