Advertisements
Advertisements
Question
It is easier to lift a heavy stone under water than in air. Explain.
Advertisements
Solution 1
It is easier to lift a heavy stone under water than in air because in water, it experiences an upward buoyant force which balances the actual weight of the stone acting downwards. Thus, due to upthrust there is an apparent loss in the weight of the heavy stone, which makes it lighter in water, and hence easy to lift.
Solution 2
It is easier to lift a heavy stone under water because in water an upthrust acts on the upward direction which reduces the apparent weight of the stone and makes it easy to lift.
RELATED QUESTIONS
What is meant by the term ‘buoyancy’ ?
A body experiences the same buoyant force while floating in water or alcohol.
Define the term Density of a substance.
How does the density of a body and that of a liquid determine whether the body will float or sink into that liquid?
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.
The area of base of a cylindrical vessel is 300 cm2. Water (density= 1000 kg m-3) is poured into it up to a depth of 6 cm. Calculate : (a) the pressure and (b) the thrust of water on the base. (g = 10m s-2.
You are provided with a hollow iron ball A of volume 15 cm3 and mass 12 g and a solid iron ball B of mass 12 g. Both are placed on the surface of water contained in a large tub.
- Find upthrust on each ball.
- Which ball will sink? Give a reason for your answer (Density of iron = 8.0 g cm-3)
A homogeneous block floats on water (a) partly immersed (b) completely immersed. In each case state the position of centre of buoyancy B with respect to the centre of gravity G of the block.
Pressure in a water pipe on the ground floor of a building is 100,000 Pa. Calculate the pressure in the water pipe on the first floor at a height of 3 m. [Density of water = 1000 kgm−3 ; g = 10 ms−2]
What do you mean by buoyancy?
