A rubber (eraser) $3\mathrm{cm}\times 1\mathrm{cm}\times 8\mathrm{cm}$ is clamped at one end with $8\mathrm{cm}$ edge vertical. A horizontal force of $2.4\mathrm{N}$ is applied at the free end (the top face). If the shear modulus of the rubber is $1.6\times {10}^5{\mathrm{Nm}}^{-2}$, then the horizontal displacement of the top face will be