Using energy: EP, B - Ffd = EK,B + EK,D (potential energy loss of block - frictional work = kinetic energy of the block + rotational kinetic energy of the drum. We are solving for v of the block and the velocity of the rope at the edge of the drum.
mBgh - Ffd = (1/2)mBv2 + (1/2)Iω2
We know that h = dsinθ = d/2, ID = (1/2)mDr2 ,(assuming drum is a solid cylinder) ,ω = v/r, and Ff = mgμcosθ
mBgd/2 - mgμcos(30) = (1/2)mBv2 + 1/2((1/2)mDr2)(v/r)2 (last term is (1/4)mDv2)
Now, plug in and solve for v.
Please consider a tutor. Take care.