According to the superposition principle of waves, A. when two wave pass through the same material they always double in amplitude. B. many different waves can pass through the same point at once. C. when two waves pass through the same material they always cancel each other out. D. only one wave is able to pass through a single point at a single time.

Asolid round steel rod 6.25 mm in diameter and 375 mm long is rigidly bonded to the end of solid square brass rod 25 mm on a side and 300 mm long. the geometric axes of the bare are along the same line. an axial tensile force of 5.4 kn is applied at the extreme ends of the assembly. for steel e = 200 gpa and for brass e = 90 gpa. determine the total elongation for the assembly.