A metallic bar of Young's modulus, 0.5 x $10^{11}$ $Nm^{-2}$ and coefficient of linear thermal expansion 10^{-5} ^\circ $^{-1}$ . Length 1m and area of cross-section $10^{-3}$ $m^2$ is heated from $0^\circ$ C to $100^\circ$ C without expansion or bending. The compressive force developed in it is: