Negative mass using negative mass that requires no energy input and no reaction mass to achieve arbitrarily high acceleration. Forward also coined a term, "nullification", to describe what happens when ordinary matter and negative matter meet: they are expected to be able to cancel out or nullify each other's existence. An interaction between equal quantities of positive mass matter (hence of positive energy ) and negative mass matter (of negative energy ) would release no energy, but because the only configuration of such particles that has zero momentum (both particles moving with the same velocity in the same direction) does not produce
Variable-mass system on a body (F = 0) the variable-mass system motion equation reduces to If the velocity of the ejected propellant, v, is assumed have the opposite direction as the rocket's acceleration, dv/d"t", the scalar equivalent of this equation can be written as from which d"t" can be canceled out to give Integration by separation of variables gives By rearranging and letting Δ"v" = "v" - "v", one arrives at the standard form of the ideal rocket equation: where "m" is the initial total mass, including propellant, "m" is the final total mass, "v" is the effective exhaust velocity (often denoted