I have a bicycle frame. I want to analyze this frame as a spring mass system. What details i should know. I should know the frame's stiffness. ok let us say it as x. Then the centre of gravity of the frame. Let us say it is also known. But now the frame can be pulled or pushed and then released from any point on it so that it vibrates. (unlike a simple spring mass system where the mass is separate and is pulled through some distance and released to induce vibration). How can such a system's natural frequency or how dynamics can be done on this?