Hello everyone, I hope someone can help me with this simple harmonic motion question I've been trying it for about an hour now and I think i may have found the problem but I want to run it by someone else :) I'm taking this Phsyics 12U course (Uni prep for Ontario, Canada) through correspondence and all I have to go by are the work books that I have received. 1. The problem statement, all variables and given/known data My work book gives me a bunch of formulas for harmonic motion, those formulas are what I am using to re-arrange and sub and so on. Prove that Max Speed of a mass on a spring is given by 2 * pi * f * A So after re-arranging and all that fun stuff I get as far as vmax= sqrt(k/m) * A =============================================== so now the speed of the mass will be at max when it is right at equilibrium (x = 0) and the potential energy will be zero and the kinetic energy will be max So then I get this formula using energy equations, (Ek = kinetic energy, m = mass) vmax = sqrt(2 * Ek / m) now we can get Ek another way, and that is using the total energy of the system equation and this is where i get hung up in my workbook, it has the total energy of the system as Et = kA^2 the total energy is all kinetic in this case so we can sub Ek for Et so I try to plug that into vmax = sqrt(2 * Ek / m) and I end up with sqrt(2k/m) * A which kind of looks like the 2 * pi * f * A rearranged except for that useless 2 in the numerator! :@ so then I research this using google and on wikipedia it has the total energy of a spring mass system as Et = (kA^2) / 2 so this formula has the same thing except the 2 in the denominator I then check another site and it also has the 2 in the denominator and it clicks, i put this formula in the equation instead and it all works out! so is my workbook giving me bad information?? is the total energy of a Spring Mass system given as Et = (k * A^2) or Et = (K * A^2) / 2 ??? thanks in advance for all of the help!