  Second, Leibniz is similarly able to argue that the quantity of  vis viva (mv2) is an adequate  measure of force. For, the quantity of vis viva of  the four pound brick falling from a height of one meter =  (1m/s)2 × 4 lbs = 1 m/s × 4lbs = 4 units, and the quantity of vis viva of the one pound brick  falling from a height of four meters = (2 m/s)2 × 1  lbs = 4 m/s × 1 lbs = 4 units. Thus if force is measured by  the quantity of vis viva rather than the quantity  of motion the equality of the force acquired by the one pound body  during its four meter fall will be equal to the force acquired by the four pound body during its one meter fall. 