1. Do you have a family member who uses your
toothpaste. Doesn't it make you angry when they don't
squeeze it from the bottom. The fact that you can
squeeze it from the bottom and still have the toothpaste
come out is an example of another fluid principle

2. 3.4 Applying Pascal’s Principle
Pascal’s principle states that in an
enclosed fluid, an externally applied
pressure is transmitted uniformly in
all direction.

3. Hydraulic System
Pressure at 1 is same as pressure at 2, P1 = P2
input force = output force F1= F2 V1 = V2
input area output area A1 A2 A1d1 = A2d2
d1 d2V1
V2

4. Hydraulic System
• Hydraulic systems act as a force multiplier.
They multiply the input force by a certain
factor to gain a larger output force.
• Hydraulic system must not contain any air
bubbles in any portion of its hydraulic fluid
system. The presence of air bubbles will
reduce the efficiency of the system as part of
the applied force will be used up to compress
the air bubbles.

5. Application of Pascal’s Principle
• Hydraulic pumps can lift large objects, like
the car, by using a minimal force on the
handle.

6. Hydraulic Brake
• A small force acting at the pedal can transmit a large
force to all wheels simultaneously to stop the car.
• It is because the pressure will be transferred through the
pedal brake liquid to car’s tyre .
• If there is a leakage in the tube, the pressure applied at
the pedal is used to expel some of the fluid out. Thus the
efficiency of the brake system is affected.

7. Homework
3.4 Questions (pg 92)
Do in book 1, Show A,B,C or D and working.
No need copy question.
Pass up book 1 and book 2 on Monday.(9/7)