A circular disc of mass M and radius R is rotating about its axis with uniform speed. Its kinetic energy is?

Mv²

½Mv²

½ × Mv²

MV²

Rotational kinetic energy of a disc about its center:

K.E = (1/2) I ω², where I = moment of inertia.

For a disc, I = (1/2)MR²,

So, K.E = ½ × (½ MR²) × ω² = ¼ MR²ω²

If linear velocity v = Rω, then

K.E = ¼ Mv²