I can't figure out how to find the mass of the clothesline, even though given the density, because the radius or crossectional area is not given. Any input on this would be appreciated. A clothesline of length 10m is stretched between a house and a tree. The clothesline is under a tension of 50N and it has a density of 6x10^-3 kg/m. How long does a wave pulse take to travel from the house to the tree and back? I have a couple of questions that use the density and they all allude me. Thanks!