By using the expression for the shear stress derived in BSL book $,$ show that the shear force on a sphere spinning at a constant angular velocity in a Stokes$$ flow, is zero. This means that a neutrally buoyant sphere $($weight equal buoyancy force$)$ that is made to spin in a Stokes$$ flow, will neither rise nor fall, nor translate in any preferential direction in the $($x$-$y$)$ plane.