Physics of Vertebrae?

Between each pair of vertebrae in the spinal column is a cylindrical disc of cartilage. Typically, this disc has a radius of about 3.1 x 10-2 m and a thickness of about 1.4 x 10-3 m. The shear modulus of cartilage is 1.2 x 107 N/m2. Suppose a shearing force of magnitude 12 N is applied parallel to the top surface of the disc while the bottom surface remains fixed in place. How far does the top surface move relative to the bottom surface?