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प्रश्न
State the principle of floatation.
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उत्तर
“When a solid is floating in a fluid, the weight of whole solid acting vertically downward at its "Centre of Gravity", is equal to the weight of the fluid displaced by the "Immersed" part of solid acting upward, at its "centre of Buoyancy" or at the centre of the "Bulk of liquid" displaced.”
OR
“The weight of a floating body is equal to the weight of the liquid displaced by its "Submerged" part.”
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संबंधित प्रश्न
When a piece of wood is suspended from the hook of a spring balance, it reads 70 gf. The wood is now lowered into water. What reading do you expect on the scale of spring balance?
For a floating body, its weight W and upthrust FB on it are related as :
A weather forecasting plastic balloon of volume 15 m3 contains hydrogen of density 0.09 kg m-3. The volume of equipment carried by the balloon is negligible compared to its own volume. The mass of an empty balloon alone is 7.15 kg. The balloon is floating in air of density of 1.3 kg m-3. Calculate:
(i) The mass of hydrogen in the balloon,
(ii) The mass of hydrogen and balloon,
(iii) The total mass of hydrogen, balloon and equipment if the mass of equipment is x kg,
(iv) The mass of air displaced by balloon and
(v) The mass of equipment using the law of floatation.
A hollow metal cylinder of length 10 cm floats in alcohol of density 0.80 g cm-3, with 1 cm of its length above it. What length of cylinder will be above copper sulphate solution of density 1.25 g cm-3?
A test tube loaded with lead shots, weighs 150 gf and floats upto the mark X in water. The test tube is then made to float in alcohol. It is found that 27 gf of lead shots have to be removed, so as to float it to level X. Find R.D. of alcohol.
A test tube loaded with lead shots weighs 25 gf and floats upto the mark X in water. When the test tube is made to float in brine solution, it needs 5 gf more of lead shots to float upto level X. Find the relative density of brine solution.
Assertion: To float, body must displace liquid whose weight is equal to the actual weight.
Reason: The body will experience no net downward force in that case.
If you put one ice cube in a glass of water and another in a glass of alcohol, what would you observe? Explain your observations.
Differentiate positive & negative buoyant.
