A cubical block of side a is moving with velocity v on a horizontal smooth plane as shown. It hits a ridge at point O. The angular speed of the block after it hits O is:

Options

A. 3v/4a
B. 3v/2a
C. `sqrt3 v// sqrt2 a`
D. Zreo

Answer

A

Explanation

Net torque about O is zero. Therefore, angular momentum (L) about point o will be conserved
`or, L_i=L_f`
`Mv(a/2)=l_0omega=(l_"com"+Mr^2)omega`
`{((Ma^2)/6)+M(a^2/2)}omega`
`=2/3Ma^2omega`
`:. omega=3v//4a`