Now let's add something to our object in outer space. Instead of the object floating motionless let's say it's drifting to the right. There are still no other objects around for billions of kilometers. Draw the free-body diagram of this object.

Run these statements through your head when you draw your free-body diagram:

• If I draw a force on a free-body diagram I have to be able to answer the question "What exerts that force?"
• If this is the free-body diagram I come up with for the object, what will happen to the object's motion?

What if the object was drifting to the right at twice the speed? Would your free-body diagram change? If so, how?

Even though it is moving the object at the present time is essentially interacting with nothing, and hence there are still no forces on the free-body diagram.

What will the object do? It will keep drifting to the right. Its motion will not change.