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Question
The mass of a block made of certain material is 13.5 kg and its volume is 15 × 10-3 m3.
(a) Calculate upthrust on the block if it is held fully immersed in water.
(b) Will the block float or sink in water when released? Give a reason for your answer.
(c) What will be the upthrust on block while floating?
Take density of water = 1000 kg m-3.
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Solution
Mass of a block = 13.5 kg
Weight of the block = 13.5 kgf
Volume = 15 × 10-3 m-3
Density of water = 1000 kgm-3
(a) Upthrust = Volume of block × density of water × g
= 15 × 10-3 × 1000 × g
= 15 kgf
(b) The block will float since the upthrust on it is more than its weight (= 13.5 kgf) when fully immersed in water.
(c) While floating , upthrust = 13.5 kgf (weight of the body)
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