A block of mass 10 kg is in contact against the
inner wall of a hollow cylindrical drum of
radius 1 m. The coefficient of friction between
the block and the inner wall of the cylinder is
0.1. The minimum angular velocity needed for
the cylinder to keep the block stationary when
the cylinder is vertical and rotating about its
axis, will be : (g = ``10m/s^2`` )
(1) ``\sqrt10`` rad/s
(2)``\frac {10}{2\pi} rad/s``
(3) 10 rad/s
(4) 10 ``\pi`` rad/s