Two rolling objects (conceptual)
Note: If you want to answer this question correctly, you should draw the appropriate FBD's.
A hoop (I=mR2) is being held at rest on a sphere as indicated in the figure below. Both objects have the same mass and same radius.
The sphere is pinned through its center so it is free to rotate, but will not translate. The hoop is then released so that it rolls without slipping along the sphere until the hoop comes off of the sphere.
In which direction does the sphere rotate?
The sphere rotates counter-clockwise.
The sphere does not rotate.
The sphere rotates clockwise.
If you compare the angular speed of the hoop to the angular speed of the sphere just as the hoop comes off
The sphere rotates with less angular speed.
The sphere rotates with greater angular speed.
The sphere does not rotate so it has no angular speed.