gfak25's point is that there is no question in there! you give us a formula, and two numbers. Yes, we can guess, as mrjeffy321 did, that "d" is "Distance", and we are given "t" so maybe the problem is to find a.Thermal said:Unfortunately, I can't help him. The problem is this: a=2d/t(squared). Distance=30 cm. t=.9 seconds.