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Archimedes’ Principle. Dynamics lesson 3. The principle. Any body sunk in a liquid supports an upwards force where the magnitude is equal to the weight of the displaced liquid.
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Archimedes’ Principle Dynamics lesson 3
The principle • Any body sunk in a liquid supports an upwards force where the magnitude is equal to the weight of the displaced liquid. • Any body sunk in a liquid supports an upwards force where the magnitude is equal to the weight of the displaced liquid. • Any body sunk in a liquid supports an upwards force where the magnitude is equal to the weight of the displaced liquid. • Any body sunk in a liquid supports an upwards force where the magnitude is equal to the weight of the displaced liquid. The new force is named: E BUOYANCY liquid being displaced P or UPTHRUST
Floating or sinking When introducing a body in a liquid, two situations may happen: buoyancy = weight buoyancy < weight E = P E < P E P P E The body FLOATS The body SINKS
A densities ‘affair’ Buoyancy E E = mld · g ld = liquid being displaced b = body Body’s weight P P = mb· g floating sinking E = P E < P mld · g= mb · g mld = mb mld · g< mb · g mld < mb rl· Vld= rb· Vb rl· Vld< rb· Vb rl> rb rl< rb Vld< Vb as simulation
Eureka!! • In ancient Greece, a king ordered a gold crown. • He gave a mass of gold to the jeweller. • The king received a golden crown that weighted exactly the same mass. • The king asked Archimedes to work out if the crown was really made of gold, without damaging it. • Archimedes discovered it by having a bath… How?