Rolling Without Slipping :
In case of combined translatory and rotatory motion if the object rolls across a surface in such a way that there is no relative motion of object and surface at the point of contact, the motion is called rolling without slipping.
By the law of conservation of energy
[∴ As v = Rω]
[∴ As Ip = I +mR2]
(1) Linear velocity of different points in rolling :