Application of Liquid Pressure - Hydraulics

1. Hydraulics
and the use of liquid pressure

2. The important features of
pressure in liquids
• Liquids will transmit pressure throughout
the liquid, regardless of the shape of
the container
• A force therefore can be applied
wherever you want it
• The force can be multiplied according
the the area of the pistons used to push
down on the water

3. Examples of the use of
hydraulics
• Car brakes
• Car jacks
• Fork lift trucks
• Lifts
• bulldozers
• Television cameras

4. How car brakes use hydraulics
• A small force on the brake pedal
will act on a piston with a small
area
• The small piston pushes against the
brake fluid
• The pressure exerted is transmitted
to all parts of the liquid
• The pressure acts against four
bigger pistons with larger areas
• The large pistons will multiple the
force and cause the brake pads to
push against the wheels
• As pressure is transmitted equally
throughout the liquid, each brake
works evenly too

5. Hydraulic brake
• The diagram shows a
simple brake where a pedal
will push down on the
smaller master piston
• The force pushing down
will put the liquid under
pressure
• The pressure is
transmitted through the
liquid and against the slave
piston
• The pressure causes the
slave piston to exert a
force where it is needed

6. Using the formula P=F/A
• What is the pressure exerted
on the liquid by the slave
piston?
Answer:
Pressure = 10N / 5cm2
= 2 N/cm2
• Calculate the area of the
slave piston that will lift a
100N load
Answer:
Area = force / pressure
= 100N / 2 N/cm2
Master
Piston
Is 5 cm2
10N
Slave
piston

7. More questions on hydraulics
1. What will the force (F1) need to be to exert a pressure
of 20 N/cm2 ?
2. Calculate the weight (F2) that can be lifted by the
slave piston.
Answers: 1. Force = 20 N/cm2
x 10cm2
= 200N
2. Force = 20 N/cm2
x 100cm3
= 2000N
Master
piston
= 10cm2 Slave piston
= 100cm2

8. Summary of the principles of
hydraulics
• Pressure is transmitted throughout a liquid
• A force may be applied anywhere to the liquid
• All hydraulic systems use a small master piston
and a large slave piston
• A small force is used to create a very big force
• The small master piston is used to apply a force
• The slave piston is always bigger than the
master piston
• The larger slave piston will multiply the
original force put on the master piston

9. This powerpoint was kindly donated to
www.worldofteaching.com
http://www.worldofteaching.com is home to over a
thousand powerpoints submitted by teachers. This is a
completely free site and requires no registration. Please
visit and I hope it will help in your teaching.

10. This powerpoint was kindly donated to
www.worldofteaching.com
http://www.worldofteaching.com is home to over a
thousand powerpoints submitted by teachers. This is a
completely free site and requires no registration. Please
visit and I hope it will help in your teaching.