When a dense object sinks in water, it sinks at a constant rate, because the buoyancy and fluid drag counteract the weight of the object. But if there is no resultant force, then why does the object slow down when it enters the water? Eg. if it's traveling at 2 m/s when it enters the water, shouldn't it continue to travel at 2m/s inside the water, because the forces are balanced? Is there some kind of force that slows down the object WHILE it's entering the water, but doesn't do anything once the object is fully in the water?