Physics
Physics
Problem
Why does wearing an inflated life-jacket help a swimmer to float more easily in water?Intuitive explanation
Buoyancy depends on the volume of water displaced, not the mass of the object. An inflated life-jacket increases your total volume significantly while adding almost no weight, so the buoyant force (equal to the weight of displaced water) becomes much larger than your body's weight. This shifts the balance toward upward force, making it easier to stay afloat with minimal effort.
Intuitive explanation
Buoyancy depends on the volume of water displaced, not the mass of the object. An inflated life-jacket increases your total volume significantly while adding almost no weight, so the buoyant force (equal to the weight of displaced water) becomes much larger than your body's weight. This shifts the balance toward upward force, making it easier to stay afloat with minimal effort.