Q75 of 176 Page 127

Giving reasons state the reading on a spring balance when it is attached to a floating block of wood which weighs 50 g in air.

The reading on spring balance will be zero. This is because the weight of floating block of wood is fully supported by the liquid in which it is floating and hence it does not exert any force on the spring balance.


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Two different bodies are completely immersed in water and undergo the same loss in weight. Is it necessary that their weights in air should also be the same? Explain.

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A body floats in kerosene of density 0.8 ×103 kg/m3 up to a certain mark. If the same body is placed in water of density 1.0×103 kg/m3, will it sink more or less? Give reason for your answer.

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If a fresh egg is put into a beaker filled with water, it sinks. On dissolving a lot of salt in the water, the egg begins to rise and then floats. Why?

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A beaker full of water is suspended from a spring balance. Will the reading of the balance change:

(a) If a cork is placed in water?


(b) If a piece of heavy metal is placed in it?


Give reasons for your answer.