Hi there.

I'm looking for an equation to calculate the rate at which 2 bodies of known mass m1 and m2 will accelerate towards each other for any given distance. Just want to check that I've got this right.

Using the gravitational equation

F=G*m1*m2/r^{2}

then substitute

F=ma where m = m1+m2

therefore

(m1+m2)a = G * m1 * m2/r^{2}

therefore

a = G * m1 * m2 / (m1+m2)r^{2}