 Galileo proposed that a falling body would fall with a uniform acceleration , as long as the resistance of the medium through which it was falling remained negligible , or in the limiting case of its falling through a vacuum . He also derived the correct kinematical law for the distance travelled during a uniform acceleration starting from rest — namely , that it is proportional to the square of the elapsed time ( d ∝ t 2 ) . Prior to Galileo , Nicole Oresme , in the 14th century , had derived the times @-@ squared law for uniformly accelerated change , and Domingo de Soto had suggested in the 16th century that bodies falling through a homogeneous medium would be uniformly accelerated . Galileo expressed the time @-@ squared law using geometrical constructions and mathematically precise words , adhering to the standards of the day . ( It remained for others to re @-@ express the law in algebraic terms ) . 
