A copper (Young's mudulus 1.1 x 10^11 N/m2) cylinder and a brass (Young's mudulus 9.0 x 10^10 N/m2) cylinder are stacked end to end, as in the drawing. Each cylinder has a radius of 0.13 cm. A compressive force of F = 5000 N is applied to the right end of the brass cylinder. Find the amount by which the length of the stack decreases?