To determine the direction of angular velocity, we use the right-hand rule. If the fan is rotating counterclockwise, the angular velocity vector points along the negative \( k \)-axis, indicating the direction of rotation.
A wooden block of mass M lies on a rough floor. Another wooden block of the same mass is hanging from the point O through strings as shown in the figure. To achieve equilibrium, the coefficient of static friction between the block on the floor and the floor itself is