Suppose I have 2 bodies, M1 and M2. Assuming that no other forces are acting on them aside from gravity, what is the nature of their acceleration over time? As they approach each other, and their distance decreases, does their acceleration also increase? If so, what is the rate at which this occurs, and with what equation might one find the acceleration or velocity at a specific time, t? Does it have something to do with F=d(ma)/dt and F(G)? Also, how might one calculate the gravitational attraction between more than two bodies? How might one determine the acceleration of each body at a given time as they approach eachother? I only have a limited understanding of calculus (calc 1) and vectors, but do not hesitate to explain in full. Thanks for your time. Oh yes- and do orbits come into play here?