A cubical block of side  30cm is moving with velocity 2m/s  on a smooth horizontal surface. The surface has a bump at a point O as shown in figure. The angular velocity (in rad/sec) of the block immediately after it hits the bump, is:

1. Given Side of block  a=30 cm=0.3 mVelocity  v=2 m/sBefore hitting point O ,We know angular momentum L=mvr=mva2Also, after hitting point O, L=Iω2. Using conservation of angular momentum,  mva2=Iω3. Moment of inertia (I) of cubical block about one edge is given byI=ma26+a22 ∴ω=m.2a2ma26+a22 ⇒ω=128a=32×0.3=102=5 rad/sec Therefore, the correct answer is (B).