Use Addforce to reach a destination at a certain time?

I’m wanting to set a distance and use Addforce to have the game object speed up or slow down in order to reach that point at the end of 5 secs.

Calculating the right amount of AddForce is possible, but it is much easier just to set the velocity. So if you were pointed at the destination and the distance between you and the destination was 20 units, and you wanted to reach the destination in five seconds:

rigidbody.velocity = transform.forward * 20.0 / 5.0;