I have a spring of known rate preloaded inside a device where it is contacting a free object. The spring is pulled back a known distance and then released. The spring continues until it reaches the stop which is where its initial preload is and then the object continues. I need to know the acceleration of that object so I can determine the force. I know the mass of the object. Here's some number to go with it to help. Spring free length = 2.300" Preloaded Height = .866" Spring Rate = 4.255 lbf/in I am compressing the spring .095" more to a height of .771" then letting go. The object has a mass of 4.9g Thanks for the help.