Advertisements
Advertisements
Question
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.
Advertisements
Solution
Given that the force applied to the smaller piston A is 4 kg
Area of cross-section of piston A = 8 cm²
Area of cross-section of piston B = 320 cm²
(i) Pressure acting on piston A in the downward direction = `"Thrust"/"Area"`
= `(4 "kg")/(8 "cm"^2)`
∴ Pressure acting on piston A = 0.5 kg cm-2
(ii) According to Pascal's Law
Pressure acting on piston B = Pressure acting on Piston A = 0.5 kg cm-2
(iii) Thrust acting on piston B in the upward direction
= Pressure × Area of B
= 4 kg × `(320 "cm"^2)/(8 "cm"^2)`
∴ Thrust acting on piston B in the upward direction = 160 kgf.
RELATED QUESTIONS
What happens to the buoyant force as more and more volume of a solid object is immersed in a liquid ? When does the buoyant force become maximum ?
A cork piece floats on water surface while an iron nail sinks in it. Explain the reason.
What is meant by pressure? State its S.I. unit.
How does the liquid pressure on a diver change if :
The diver moves horizontally?
Complete the following sentence :
A piece of wood is held under water. The upthrust on it will be ___________ the weight of the wood piece.
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 block of wood is floating on water with its dimensions 50 cm x 50 cm x 50 cm inside water. Calculate the buoyant force acting on the block. Take g = 9.8 N kg-1.
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?
How is thrust different from pressure?
Salt water provides less buoyant force than freshwater.
