The exercise is: There are three point-like objects in space - far from any other objects - such that their initial velocities are zero, and the distance between any two is the same d. Two of the objects have the same mass of m, and the mass of the third one is 2m. Due to the gravitational force the objects begin to move and they collide with each other. a) How much distance do they cover until they meet? b) How much time elapses until the collision of the objects? I tried to use F=ma, F=G*m1*m2*1/r2, and a=d2x/dt2 to get the time-distance function, but i could't do anything with the sin(alpha). The other problem is i can't find out the lane of the objects.