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Question
A rubber ball floats on water with its 1/3rd volume outside water. What is the density of rubber?
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Solution
Let the volume of the ball be V .
Volume of ball above the surface of water = `1/3`V
∴ Volume of ball immersed in water = `"V" - 1/3"V" = 2/3 "V"`
By the principle of floatation on,
`"Volume of rubber ball immersed"/"Total volume of rubber ball" = "Density of rubber"/"Density of water"`
or , `2/3 = "Density of rubber"/1000`
or , Density of rubber ball = `1000 xx 2/3 = 666.7 "kgm"^3 ≈ 667 "kgm"^3`
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