Problem: A 52 kg stone is being removed from a waterfront that is being made over into a beach. What does the stone weigh? What does it appear to weigh in the water?

Solution: The weight in air is its "true" weight (at least, on Earth at sea level), and it is:

In the water, its weight appears to be less because of the buoyant force of the water. (From reference tables, the specific gravity of granite is approximately 2.7.) Using Archimedes' Principle,

The apparent weight is the difference, which is 321 N.