Theory of Machine
A rigid body, under the action of external forces, can be replaced by two masses placed at a fixed distance apart. The two masses form an equivalent dynamical system, if
The sum of the two masses is equal to the total mass of body
All of these
The center of gravity of the two masses coincides with that of the body
The sum of mass moment of inertia of the masses about their center of gravity is equal to the mass moment of inertia of the body
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.