1. The problem statement, all variables and given/known data A 75 g bungee cord has an equilibrium length of 1.20 m. The cord is stretched to a length of 1.80 m, then vibrated at 20 Hz. This produces a standing wave with two antinodes. What is the spring constant of the bungee cord? 2. Relevant equations f=nv/2L 3. The attempt at a solution Two anti-nodes mean 3 harmonics f = 20Hz n = number of harmonics L = length v = velocity 20 = nv/(2L)=3v/(2L) v = 20/3*2*1.8 =24m/s F = tension v^2 = F/(linear mass density) F = 24^2 * 0.075/1.8 F = 24N F = kx k =F/x k = 24/(1.8-1.2) = 40N/m i It doesn't seem to be right though!