Galileo experimented with balls rolling on inclined planes

If an angle of inclined plane is 0 degree, the acceleration down the plane must be 0. If an angle is 90 degree, the acceleration will be the same as gravity, 9.8m//s If the angle is 2 0-90 then the acceleration is defined as g sin(the angle), where g = 9.8m/s a = gsin sin(0) = 0 a max = 0 sin(90) = 1 a max = g = 9.8 m/s²