The figure below shows a planar mechanism with single degree of freedom. The instant center $${{\rm I}_{24}}$$ for the given configuration is located at a position.

The circular disc shown in its plan view in the figure rotates in a plane parallel to the horizontal plane about the point $$O$$ at a uniform angular velocity $$\omega $$. Two other points $$A$$ and $$B$$ are located on the line $$OZ$$ at distances $${r_A}$$ and $${r_B}$$ from $$O$$ respectively.

The velocity of point $$B$$ with respect to point $$A$$ is a vector of magnitude

The circular disc shown in its plan view in the figure rotates in a plane parallel to the horizontal plane about the point $$O$$ at a uniform angular velocity $$\omega $$. Two other points $$A$$ and $$B$$ are located on the line $$OZ$$ at distances $${r_A}$$ and $${r_B}$$ from $$O$$ respectively.

The acceleration of point $$B$$ with respect to point $$A$$ is a vector of magnitude

For the audio Cassette mechanism shown in Figure given below where is the instantaneous center of rotation (point) of the two spools?