### 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

• 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

• 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