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प्रश्न
What is the cause of upthrust? At which point can it be considered to act?
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उत्तर
A liquid contained in a vessel exerts pressure at all points and in all directions. The pressure at a point in a liquid is the same in all directions - upwards, downwards and sideways. It increases with the depth inside the liquid.
When a body is immersed in a liquid, the thrusts acting on the side walls of the body are neutralized as they are equal in magnitude and opposite in direction. However, the magnitudes of pressure on the upper and lower faces are not equal. The difference in pressure on the upper and lower faces cause a net upward force (= pressure x area) or upthrust on the body.
It acts at the centre of buoyancy.
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संबंधित प्रश्न
A body floats in a liquid when its weight becomes equal to the weight of the liquid displaced by its submerged part.
Which of the following will sink or float on water? (Density of water = 1 g Cm-3)
body D having density 0.85 g m-3
How does the pressure exerted by thrust depend on the area of surface on which it acts? Explain with a suitable example.
A tall vertical cylinder filled with water is kept on a horizontal table top. Two small holes A and B are made on the wall of the cylinder, A near the middle and B just Below the free surface of water. State and explain your observation.
How does the liquid pressure on a diver change if:
the diver moves to the greater depth
A simple U tube contains mercury to the same level in both of its arms. If water is poured to a height of 13.6 cm in one arm, how much will be the rise in mercury level in the other arm?
Given : density of mercury = 13.6 x 103 kg m-3 and density of water = 103 kg m-3.
Prove that the loss in weight of a body when immersed wholly or partially in a liquid is equal to the buoyant force (or upthrust) and this loss is because of the difference in pressure exerted by liquid on the upper and lower surfaces of the submerged part of body.
The S.I. unit of upthrust is :
Two identical pieces, one of ice (density = 900kg per meter cube) and other wood (density = 300kg per meter cube) float on water.
- Which of the two will have more volume submerged inside water
- Which of two will experience more upthrust due to water.
Calculate the hydrostatic pressure exerted by water at the bottom of a beaker. Take the depth of water as 40 cm, the density of water 1000 kgm−3 and g = 9.8 ms−2.
