Here's what's true about an object moving in the same direction at a constant speed for 4 hours:

* It has a constant velocity. Velocity includes both speed and direction. Since both are constant, the velocity is also constant.

* It travels a distance that is directly proportional to the time. The longer it travels, the farther it goes. This is because distance = speed x time.

* It experiences no acceleration. Acceleration is a change in velocity. Since the velocity is constant, there is no acceleration.

Let me know if you'd like more explanation on any of these points!