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प्रश्न
Why is the tip of an allpin made sharp?
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उत्तर
The tip of an allpin is made sharp so that large pressure is exerted at the sharp end and it can be driven into with less effort.
संबंधित प्रश्न
What is the scientific name of the 'upward force' acting on an object immersed in a liquid?
Fill in the blank with suitable word :
It is the................. force which makes objects appear lighter in water.
Relative density of a substance is expressed in g cm-3.
What is the unit of relative density?
State whether thrust is a scalar or vector?
The diagram below in Fig. 4.12 shows a device which makes the use of the principle of transmission of pressure.
- Name the parts labelled by the letters X and Y.
- Describe what happens to valves A and B and to the quantity of water in the two cylinders when the lever arm is moved down.
- Give reasons for what happens to valves A and B in part (ii).
- What happens when the release valve is opened?
- What happens to valve B in cylinder P when the lever arm is moved up?
- Give a reason for your answer in part (v).
- State one use of the above device.
Two cylindrical vessels fitted with pistons A and B of area of cross-section 8 cm2 and 320 cm2 respectively are joined at their bottom by a tube and they are completely filled with water. When a mass of 4 kg is placed on piston A, Find:
- the pressure on piston A,
- the pressure on piston B, and
- the thrust on piston B.
A body experiences an upthrust F1 in river water and F2 in sea water when dipped up to the same level. Which is more, F1 or F2? Give reason.
A beaker contains a liquid of density ‘ρ’ up to height ‘h’ such that ‘PA’ is atmospheric pressure and ‘g’ is the acceleration due to gravity. Answer the following questions:
- What is the pressure on the free surface of the liquid?
- What is the pressure on the base of the beaker?
- What is the lateral pressure at the base on the inner walls of the beaker?
Complete the analogy.
Downward force : Weight :: Upward force offered by liquid : _____.
