1 KEYS OF UNDERSTANDING GRAVITY MACHINES OF

The goal of this work is of to clarify some issues concerning two inventions of Serbian inventor Veljko Milkovic. The first invention is two-stage mechanical oscillator and second one is inertial propulsion cart. Analysis is based on works of Jovan Bebic, Ljubo Panic, Colin Gauld and other works found on the inventor's site www.veljkomilkovic.com. Claim that two-stage mechanical oscillator creates free energy using gravity energy as perpetuum mobile raised a lot of discussion questions and suspicions. Several scientists also devoted some time to create mathematical models and analyze it. I had a chance to see one such work by well known scientist sent to a person on the site as reply to his work. He used well known Lagrangian technique to analyze total energy (kinetic and potential) of the whole system and found no accumulation of total energy in the time. However, I was able to find two problems in the model. First problem could be easy noticed by a person who actually saw oscillator working and second problem I noticed after I tried to build mechanical feedback loop and failed in my first attempt. In this work I will try to:- point out omissions in modeling the system,- discuss issues with mechanical feedback loop,- discuss some errors in measuring and re-calculate output energy done by Jovan Bebic,- continue addressing issues started by Colin Gauld concerning Centrifugal force terminology and omission to use moment of inertia in formula for kinetic energy,- explain errors in Lead Out theory developed by Lee Cheung Kin and Lawrence Tseung,- challenge the first and third Newton's laws and confine the law of conservation of quantity of the movement of the system in analysis of inertial propulsion cart