A penny of radius a rolls without slipping on a rough horizontal table. The penny rolls in such a way that its centre G remains fixed (see given Figure). The plane of the penny makes a constant angle α with the table and the point of contact C traces out a circle with centre O and
radius a cos α, as shown. At time t, the angle between the radius OC and some fixed radius is θ. Find the angular velocity vector of the penny in terms of the unit vectors a(t), k shown. Find the velocity of the highest particle of the penny.