Physics
Answer
When handle H of lever is pressed down by applying an effort, the valve V opens because of increase in pressure in the cylinder P. The liquid runs out from the cylinder P to the cylinder Q.
As a result, the piston B rises up and it raises the car placed on the platform. When the car reaches the desired height, the handle H of lever is no longer pressed.
The valve V gets closed (since the pressure on either side of the valve becomes same) so that the liquid may not run back from the cylinder Q to the cylinder P.
Related Questions
Explain the principle of a hydraulic machine. Name two devices which work on this principle.
The diagram in figure shows a device which makes use of the principle of transmission of pressure.
(i) Name the parts labelled by the letters X and Y.
(ii) Describe what happens to the valves A and B and to the quantity of water in the two cylinders when the lever arm is moved down.
(iii) Give reasons for what happens to the valves A and B in part (ii).
(iv) What happens when the release valve is opened ?
(v) What happens to the valve B in cylinder P when the lever arm is moved up ?
(vi) Give a reason for your answer in part (v)
(vii) State one use of the above device.
Explain the working of a hydraulic brake with a simple labelled diagram.
Deduce an expression for the pressure at a depth inside a liquid.