Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities ω1 and ω2 . They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is
(a) 1/4 I(ω1 - ω2 )2
(b) I(ω1 - ω2)2
(c) 1/8 I(ω1 - ω2)2
(d) 1/2 I(ω1 - ω2)2
