Hi,
if the direction is ever changing ( like if the mouse moves around but you still want the object to ultimatly reach the mouse), then you need to computer the force by decompositing it.
1: you get the direction ( mouse position - current position)
2: normalize that direction, so that it's lenght is 1
3: multiply by a force factor
4: use it as the force.
with the above you will likely over shoot, so the force factor should be in relation with the distance, the more the distance the more the force,m but as you get closer to the final position, you decrease the force.
Bye,
Jean