The force required to compress an imperfect horizontal spring an amount x is given by F = 153x + 12.7x3 , where x is in meters and F in newtons. If the spring is compressed 1.96 m, what speed will it give to a 3.15 kg ball held against it and then released? I know that I will need to take the integral from x=0 to x=1.95, which gives me 341. How do I now get the velocity from this? Any suggestions?