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प्रश्न
How does an object’s density determine whether the object will sink or float in water?
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उत्तर
Whether an object will sink or float in a liquid is determined by the density of the object compared to the density of the liquid. If the density of a substance is less than the density of the liquid it will float. For example, a piece of wood which is less dense than water will float on it. Any substance having more density than water (for example, a stone), will sink into water.
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संबंधित प्रश्न
State the principle of floatation.
An iron nail sinks in the water while an iron ship floats on water. Explain the reason.
For a floating body, its weight W and upthrust FB on it are related as :
A body floats in a liquid A of density ρ1 with a part of it submerged inside the liquid, while in liquid B of density ρ2 it is totally submerged inside the liquid. The densities ρ1 and ρ2 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 rubber ball floats in water with 2/7 of its volume above the surface of the water. Calculate the average relative density of the rubber ball.
Name an instrument based on this principle. State two uses of the instrument that you describe.
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.
Name different types of Hydrometers with their applications.
Assertion (A): Lactometer is used to check the purity of milk.
Reason (R): Lactometer measures the cream content of milk.
