There is a displacement versus time graph of a 3.4 g mass on a spring that is in oscillatory motion. A=0.5 and the wavelength for one period is 3 s while the total time shown on the graph is 7 s. I need to find out the maximum speed of this mass. At first I thought that it would easily be the amplitude divided by the time at that highest amplitude, but obviously that was wrong. I then decided to try energy conservation, which I think is right, but I think that I am not using the correct equation. I've been trying to do some form of mgh=1/2 mv^2 and solving for v. I changed h to x and I knew that x=Acos((2pi/T)t) so I put that in for h and I tried to solve for v. I plugged in my answer and it was wrong, so I'm pretty sure that I just didn't use a correct form of this equation. How can I get a more appropriate form of this equation to use (if it is indeed the correct method) ?