1. The problem statement, all variables and given/known data http://img824.imageshack.us/img824/6466/31231242.png [Broken] http://img835.imageshack.us/img835/5220/76022234.png [Broken] It's a free fall problem and I have to calculate a = g 2. Relevant equations g = (2*(d-(vi * t)))/t^2 g = (2d)/t^2 3. The attempt at a solution I've made a graph and I've obtained a best fit polynomial equation. I know that m/t^2 = a, however if I just divide the position by time squared will that alone give me acceleration? I've tried finding initial velocity by subtracting (p2-p1)/(t2-t1) and the change in time with (t2-t1) and delta d (d2-d1) and I used this as vi for the first equation I gave...but this calculation gives me 0. Basically all the calculations cancel each other out. I've tried taking the position * 2 and dividing by t^2 and I'm still getting an acceleration value that keeps changing as the position and time increases. What am I doing wrong?