πGravity vs Buoyancyπ
Whether an object floats or sinks is a tug-of-war between two forces. Gravity drags it down; buoyancy lifts it up.
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πGravity
- βA force that pulls objects toward Earth's center
- βActs on all objects with mass, everywhere
- βPoints downward, toward the planet
- βProportional to an object's mass
- βCauses objects to fall and gives them weight
πBuoyancy
- βAn upward force exerted by a surrounding fluid
- βActs only on objects in a liquid or gas
- βEquals the weight of the fluid the object displaces
- βPoints upward, opposing gravity
- βDetermines whether an object floats or sinks
Verdict
Gravity always pulls down; buoyancy pushes up whenever an object sits in a fluid. If buoyancy is greater, the object floats; if gravity wins, it sinks. Archimedes' principle links the two.
Frequently asked
What is Archimedes' principle?+
It states that buoyant force equals the weight of the fluid an object displaces.
Why do some objects float?+
They float when the upward buoyant force is at least as large as the downward force of gravity.
Does buoyancy act in air?+
Yes. Air is a fluid, which is why helium balloons rise as buoyancy overcomes gravity.
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