# Homework Help: Interesting question about gravitational attraction,accleration and time of collision

1. Apr 7, 2009

### the-genius

1. The problem statement, all variables and given/known data
There Are two bodies with mases M1 and M2 placed in space separated by a distance D. They attract each other due to gravitational forces and hence acclerate towards each other.The problem is to Find out the time taken before their collision?

2. Relevant equations
I know that, the acceleration is provided by the gravitational force so,
a=G*M/x^2 for each body where M is the other body's mass and x is the distance from other body at that instant.
3. The attempt at a solution
I am hopless at attemting a solution.
Had my equation of accelartion, dependent on time (like a = Kt^2 + Ct ... etc) I could integrate with respect to time and find instanteneus velocity with respect to time. Then I could Integrate V.dt for a certain time to get distance, and etc. But here acceleration varies with distance,
I tried to convert dt to dx but failed.