Equivalence principle states that the gravitational and inertial forces are of similar nature and are indistinguishable. In the Newtonian form, it asserts within a windowless laboratory freely falling in a uniform gravitational field, scientists would be unaware that the laboratory is in a state of non uniform motion. All dynamical experiments would yield the same results as obtained in an inertial state of uniform motion unaffected by gravity. This was confirmed to a high degree of precision by an experiment conducted by the Hungarian physicist Roland. In Einstein’s version, the principle asserts that in free-fall the effect of gravity is totally abolished in all possible experiments and general relativity reduces to special relativity, as in the inertial state.