Waves: String Physics?? Correct my units.. 1. The problem statement, all variables and given/known data The velocity of a wave on a string depends on how hard the string is stretched and on the mass per unit length of the string. If T is the force exerted on the string and Mu is the mass/unit length, then velocity v is (I think) A piece of string 5.3m long has a mass of 15g. What must the force on the string be to make wavelength of a 125Hz wave 120cm? 2. Relevant equations 3. The attempt at a solution The given answer is 63.7N I converted wavelength lambda to 0.12M and 15g to 0.015kg.. wavelength=velocity/frequency.. so wavelength*frequency=velocity.. 0.12M*125Hz=15 m/s=velocity 15m/s = [square root of T(force)/Mu(mass length ratio)] He also gave us another equation.. instead of [square root T/Mu], there is also [square root T*length/mass] So.. 15m/s=[square root of T*5.3m/0.015kg] [(15^2 m^2)(0.015kg)]/[(s^2)(5.3m)]=T.. T=~0.636N..which would be right if it were multiplied by 100.. Anyone see where I went wrong?