7/29/2019 Bernoulli s Principle

1/13

S C I E N C E F O R M 5

THE MOTION OF

VEHICLES IN THE AIR

7/29/2019 Bernoulli s Principle

2/13

PRINSIP GERAKAN

Hot air balloon

- Hot air ballon will rise upward if its total weight is lessthat the weight of air it displaces

- Upward motion of hot air balloon is based on theprinciple of Archimedes

- a) air in the hot balloon is heated

- b) the air expand, so large volume of air is pushed

out through the hole at the bottom- c) the gas in the balloon are less dense than

surrounding.

7/29/2019 Bernoulli s Principle

3/13

PRINSIP OPERASI ENJIN JET DAN ROKET

-Enjin roket membawa bahan api hidrogen

dan oksigen dalam bentuk cecair

7/29/2019 Bernoulli s Principle

4/13

PRINSIP OPERASI ENJIN JET DAN ROKET

-The combustion of mixture of fuel and

oxygen produces a large forces

-Quantiti gas panas yang dipaksa keluar mllekzos dengan kelajuan yg sangat tinggi

menghasilkan momentum yg sgt besar

-Momentum gerakan gas akan menghasilkan

satu tujah yang kuat dan menolak roket ke

atas

7/29/2019 Bernoulli s Principle

5/13

ENJIN JET

-Pembakaran dalam yang berkuasa

tinggi

-Membawa bahan api kerosin

7/29/2019 Bernoulli s Principle

6/13

PRINSIP OPERASI ENJIN JET DAN ROKET

-Apb enjin dihidupkan, udara disedut masuk

oleh kipas turbo melalui pemampat

-Udara dimampat sehingga suhunya tinggidan dimasukkan ke ruang pembakaran

-Gas panas yang terhasil mengembang dan

dipaksa keluar dr enjin melalui ekzos

-Ini menghasilkan momentum yg sgt besar

-Momentum gerakan gas akan menghasilkan

satu tujah yang kuat dan menolak jet ke

depan

7/29/2019 Bernoulli s Principle

7/13

Bernoullis Principle

The Swiss mathematician and physicistdiscovered the Bernoulli's principle.

He found the concept of Bernoullis

principle when doing the experiment ofwater flow through the container.

Daniel Bernoulli(1700-1782)

7/29/2019 Bernoulli s Principle

8/13

Bernoullis Principle

a) As fluid moves from a widerpipe to a narrower one, thespeed of water flow will beincrease.

b) As the speed of water flow

increase, the pressure willdecrease and the watercannot go up the upside ofpipe easily.

Hence Bernoulli's conclusion: the

slower the rate of flow, the higherthe pressure, and the faster therate of flow, the lower thepressure.

7/29/2019 Bernoulli s Principle

9/13

BERNOULLIS PRINCIPLE

states that

The pressure is inversely proportional to the

speed of a moving fluid.

a) If the speed is high, the pressure is low.

b) If the speed is low, the pressure is high

7/29/2019 Bernoulli s Principle

10/13

The Effects of Bernoullis Principle

Lets do an activity together !

7/29/2019 Bernoulli s Principle

11/13

7/29/2019 Bernoulli s Principle

12/13

Aerofoil

Uplift force

7/29/2019 Bernoulli s Principle

13/13

Application of Bernoullis Principle In Life

When an aeroplanemoves forward, air movesfaster at the top of theaerofoil than below it.

The higher pressure at the bottom of the aerofoil will push it up toproduce an uplift force.

To fly, the upthrust must be greater than the weight of the

aeroplane.

This creates a lowpressure condition on thetop of the aerofoil.