Theory of Machine
The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by (where OQ = Distance between the centre of circular flank and centre of nose)
The two rigid links have no linear velocity relative to each other at the instantaneous centre.
A rigid link rotates instantaneously relative to another link at the instantaneous centre for the configuration of the mechanism considered.
The velocity of the instantaneous centre relative to any third rigid link is same whether the instantaneous centre is regarded as a point on the first rigid link or on the second rigid link.