If it goes down exactly the same way as up, it stops. That simple.
Oh, of course. Only under rare and strict circumstances in the real world. Things move, the size of movement could be small, but still moving. If everything is constant, and you threw an object up, it will stop when it reaches the highest point; relative to earth, and then comes down.
In low level speaking, it is simple. But in the real world, it's not that simple.