1. Problem statement and all known/given variables 2. Related equations W = fd Newtons kinematic equations 3. Attempt at solution For part a) since the magnitude of the work done by gravity to 2 a.u is 2500GJ I use the equation W = fd and I solve for f by dividing work by the distance 2500 = f(2a.u) (after I convert the units). For part b) I just looked at the graph and saw that the change in gravitational energy was 4500GJ so I'm assuming that's what they are asking for? For part c) since the change in work done by gravity at 6.5au is 6000, i use the equation w = fd, setting w = 6000, change f to ma, solve for a, plug that acceleration into newtons kinematic equation (vf^2 = vo^2 + 2ad) with vo being 0 , the distances cancel out and I'm left with vf = sqrt(2a) .. or see below Thanks for any input!