"Two small spheres of putty, A and B, of mass M and 3M, respectively, hang from the ceiling on strings of equal length l. Sphere A is drawn aside so that it is raised to a height h0 and then released. Sphere A collides with sphere B; they stick together and swing to a maximum height h equal to " This is an exercise I am perplexed about as to why I got the wrong answer. I used conservation of energy. Ei = mgh0 Ef = (m+3m)gh Ef = Ei mgh0 = (m+3m)gh Therefore h = (1/4)m This answer is wrong. The correct answer is (1/16)h0. Where'd I go wrong? Thanks!