A ring of radius R is rolling purely on the outer surface of a fixed pipe of radius 4R., At some instant,when ring has no angular acceleration the centre of the ring has a speed v. Then, the acceleration of the point on the ring which is in contact with the surface of the pipe is.
Acceleration of centre of ring →ac=v25R(−^j),Acceleration of point of contact w.r.t. centre of ring →ac=v2R^j
|→ac|=|→abc+→ac|=V2R−V25R=45V2R