ZIMSEC O Level Combined Science Notes: Hydraulic Jack

  • Has a large ram attached to the piston in a large cylinder

The diagram of the Hydraulic Jack. Image credit slideplayer.com

The diagram of the Hydraulic Jack. Image credit slideplayer.com

  • A piston in a small cylinder is worked by a handle
  • Pressure on this cylinder when the handle is pushed down
  • is passed on through the liquid to the ram of the larger surface area
  • The ram thus exerts a larger upwards force
Simple hydraulic jack diagram. Image credit schoolphysics.co.uk

Simple hydraulic jack diagram. Image credit schoolphysics.co.uk

  • In order to increase the distance to which it can raise the load
  • The small cylinder is fitted with vlavles
  • These valves allow exra liquid to flow through when the piston is pushed down

Calculations

  • Work done by the hydraulic machine can be calculated:
  • For example if the area of the piston is 100cm2 and
  • That of piston is 10cm2
  • If a force of 100N on piston produces pressure of:
  • \dfrac{100}{10}=10N/cm^2
  • This pressure is passed on to piston where it acts over the entire 100cm2
  • Given that:
  • \text{Pressure}=\dfrac{Force}{Area}
  • \text{Force}=\text{Pressure x Area}
  • 10N/10cm2 x 100cm2
  • 1 000N
  • A 10N force can thus lift a 1 000N loadk
  • Also a little movement can be translated into a larger movement of load using hydraulics

To access more topics go to the Combined Science Notes page