1. The problem statement, all variables and given/known data Two bodies with the same mass are connected trough a string. The tension on the string is T. Find the ressonance frequency of the system. 2. Relevant equations 3. The attempt at a solution F=m*a, 0=0 , doesn't help me much. At the ressonance frequency the wave will have 3 nodes. I know that those kind of waves have the following equation of movement: y=2*Asin(kx)cos(wt) , where k=2pi/wave length => k=2pi/2L. If i solve for x=L/2, I'll have 2Acos(wt), but I can't get rid of the t... I'm stuck here... don't know what else to do... Any hint or help will be very appreciated! Thanks.