2.6

Which part of the paper does the air move at a
high speed?
………………………………………………………
A Boeing 747 aircraft can carry 400 to 500 of
passengers. How can the plane fly with the heavy
load? Why a Formula-1 car can go through a
sharp curve while travelling at 300 km per hour?

Mark the direction of the net force acted on
the paper
What causes the movements of paper in both
activities?
………………………………………………………………
Explain how the resultant force is produced to
move the paper.
………………………………………………………………
Activity 1:
Aim: To study the relationship between speed of
flow of liquid with its pressure
A. Hold a piece of
paper. Blow air
above the paper.
 What happens to
the paper?
……………………………
……………………………

Which part of the paper has a:
Lower pressure? ……………
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
State the relationship between speed of air and
pressure.of moving air.
………………………………………………………………
………………………………………………………………
State Bernoulli’s Principle
Higher pressure? ……………

Which part of the paper does the air move at a
high speed?
………………………………………………………

Mark the direction of the net force acted on
the paper
B. Hold two pieces
of paper close to
each other and
blow steadily
into the space
between the
paper

Activity 2:
Aim: To study how fluid pressure is influenced by
speed of fluid.
1.
Flow water throught the non uniform tube.
What happens to the paper?
………………………………………………………………

Determine the regions which has:
Lower pressure? ……………
Higher pressure? ……………
 Refer to X, Y and Z: arrange the speed of water
ascending.
…………………………………………………………
 Refer to X, Y and Z: arrange the pressure of
water descending.
…………………………………………………………
 Mark the water level in the vertical tubes P, Q
and R. Explain your answer for the lowest
level.
 What happens to the ping pong ball?
………………………………………………………………
 Mark with R, the region water flows with higher
speed.
 Mark with S, region with lower pressure.
 Explain what happens to the pingpong ball.
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
……………………………………………………………..,
………………………………………………………………
1.
Diagram shows air is blown through a non
uniform tube.
………………………………………………………………
………………………………………………………………
3.

At which point air is the fastest? ..............

At which point the water pressure is the
Suspend two balloons by two threads at a
distance of 10 cm apart. Blow through the
space between the balloons with the help of a
straw. What happens to the two balloons?
Why?
lowest? ....................
 Mark the water level in the vertical tubes P,Q
and R.
………………………………………………………………
 Why water rise up in the vertical tube Q?
………………………………………………………………
......................................................................................
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
4.
2.
You are asked to take out a pingpong ball
from a filter funnel without using hand.
Support a pingpong ball in the filter funnel.
The tap is turned on to allow water to flow
through the filter funnel. Release the hand
which support the pingpong ball.
 Explain what happens to the pingpong ball if
you blow air from the bottom as in Diagram (a).
………………………………………………………………
………………………………………………………………
 You can blow air across the top of the filter
funnel as shown in Diagram (b). Explain if you
can take out the pingpong ball from the filter
funnel.

What happens at the narrow opening
when the piston is pushed into the
cylinder?
…………………………………………………………
………………………………………………………………
…………………………………………………………
………………………………………………………………
…………………………………………………………
………………………………………………………………

………………………………………………………………
How does the insecticide rise through the
metal tube?
…………………………………………………………
Activity 3
Aim: Explain applications of Bernoulli’s Principle
…………………………………………………………
1. Aerofoil
An aeroplane can fly because its cross sectional
wing has an aerofoil shape which produce a lift
force.
…………………………………………………………

How is the fine spray produced?
…………………………………………………………
3.




Draw the stream of airflow past on the
aerofoil.
Label the region with faster airflow and
slower airflow.
Label the region with high pressure and lower
pressure
Indicate the direction and label,F, the lift force
acts on the aerofoil.
Explain how the uplift force is produced to help
the plane take-off.
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
2. Penyembur racun serangga
A Bunsen Burner


Mark with X the region where gas flow
with high speed.
What happens at the jet when a Bunsen
burner is connected to the gas supply,
…………………………………………………………
…………………………………………………………
…………………………………………………………

Explain how a blue flame is produced?
…………………………………………………………
…………………………………………………………
…………………………………………………………
4. Figure (a) shows a moving ball that is not
spinning, whereas Figure (b) shows a spinning
ball that is not moving
forward.
(a)

In diagram (a), the ball is moving to the right so
air stream moves to the ............... as opposite.
In diagram (b), the ball is spinning clockwise
direction. At the bottom the air stream moves
to the .............. and at the top the air stream
5.
Sailboat
Diagram shows a sailboat moves against the
wind.
moves to the.....................
 Diagram below shows a spinning ball moving
through air.
 Compare the speed of air
stream at A and B.
……………………………………

The bottom side of the ball has ................
velocity of air because both air streams combine
as the flow of air stream is in the same direction
of spin. The top side of the ball has ....... velocity
of air as both air streams combine with the
opposite direction.

According to Bernoulli’s principle, as the
region with high velocity will produce .............

 Compare air pressure at point A and B
………………………………………………………………
 Mark with F the direction of resultant force
acts on the sail of the boat.
 Mark with X the movement direction of the
sailboat.
pressure region.
 Explain how the sailboat can move forward
against the wind.
So the bottom of the ball has .............
………………………………………………………………
pressure
region and the top of the ball has ..............
………………………………………………………………
pressure region. There is a ......................... in
………………………………………………………………
pressure and will produce a ................
……………………………………………………………...
.............. This makes the ball changing its path
in a ......... path.
………………………………………………………………
………………………………………………………………
.
………………………………………………………………
.
2.
 State two factors which influence the
magnitude of resultant force acts on the sail.
The figure shows the wing of an airplane
which is moving with a uniform acceleration
in the direction shown by the arrow.
………………………………………………………………
………………………………………………………………
6. Diagram shows the roof of a house being lifted
by strong winds.
Which of the following is true?
A. The uplift force is higher than the
weight of object
B. The resultant force in direction of the
motion of the object is zero
C. The pressure in region P is higher than
in region Q
D. The velocity of air in region P is higher
than in region Q.
3.
Diagram shows an object with an aerofoil
shape placed in a wind tunnel.
Explain how the roof is lifted.
………………………………………………………………
………………………………………………………………
Which position A, B, C and D experiences the
lowest pressure?
………………………………………………………………
……………………………………………………………...
4.
Diagram 9
shows a piece
of paper
clamped to a
retort stand.
When air at high
velocity is
blown on top of
the paper, the
edge of the
paper…
A. Will lift up
B. Will move down
C. Does not move
5.
Diagram 12 shows a student blows strongly
between two candle flames.
Tutorial 2.6
1.
Diagram below shows two similar ping-pong
balls suspended on strings of the same
length.
Which of the following diagrams shows the
condition of the ping-pong balls when air is
blown between them?
Why the candle flames approach one another
when being blown?
A. Temperature between the candle flames
becomes low
B. Pressure between the candle flames
become low
C. Exist a vacuum area between the candle
flames
D. Hot air at the bottom of the candles rises.
6.
7.
8.
Diagram 10 shows a boy
blowing over a glass rod.
Which principle explains
the situation?
A. Pasca’s principle
B. Bernoulli’s principle
C. Archimedes’ principle
D. Principle of
conservation of
momentum
10. Diagram 9
shows a pingpong ball being
pulled towards
fast flowing
water.
Which principle
explains this
situation?
A. Pascal’s principle
B. Bernoulli’s principle
C. Archimede’s principle
D. Principle of conservation of energy
1. Figure(a) shows a piece of paper hanging
from a retort stand. When air flows from the
nozzle of an air pump, the paper changes its
position as shown in Figure(b).
Which equipment works based on the
Bernoulli’s principle?
A. Suction pump
B. Bunser burner
C. Vacuum cleaner
D. Hydraulic jack
Diagram 11 shows an aerofoil attached to the
back of Formula One car.
Figure(a)
Figure(b)
(a) Compare the position of paper in Figure(a)
and Figure(b)
………………………………………………………………
(b)
Which statement is correct when the car is
moving fast?
A. Pressure at X is greater than at Y.
B. Pressure at X and Y is the same.
C. Velocity of air at X and Y is the same
D. Velocity of air at X is greater than at Y.
9.
Diagram 13 shows a top view of a sailboat
sailing against the direction of wind. (2015)
F is a force that causes the paper to change
its position. In box, X, on Figure(b) ,
indicate and label the direction of F that
acts on the paper.
(c) Explain how F is produced?
………………………………………………………………
………………………………………………………………
………………………………………………………………
………………………………………………………………
(d) (i)
Compared to the position of the paper in
Figure(b), how does the position of the
paper change when the air flows faster?
………………………………………………………………
Which direction A, B, C or D, the lift force
acting on the sail?
(ii)
Give reason to your answer in d(i).
………………………………………………………………
[1 m]
(d) Name the principle that causes the
observations in Figure (b).
………………………………………………………………
[1 m]
(c) Name the principle involved in 5(b)(iii).
(e) Name one piece of apparatus in a school
laboratory which uses the principle in(e).
………………………………………………………………
[1]
………………………………………………………………
[1 m]
2. Spm 2006 Question No. 5:
Diagram 20.1 shows the situations of a sheet of
paper before and when air is blown. Diagram 20.2
shows the situation of the canopy before the lorry
moves and when the lorry moves at high speed.
(a)
What is meant by speed?
mark]
[1
………………………………………………………………
(b) Based on Diagram 20.1 and Diagram 20.2:
(i) State two similarities for the situations in
Diagram 20.1 and Diagram 20.2.
……………………………………………………………..
………………………………………………………………
(d) Diagram 20.3 shows an instrument used to
measure the speed of air.
In Diagram 20.3, the levels of coloured water in
the U-tube are the same before air flows.
(i) Compare the speeds of air at P and at Q
………………………………………………………………
[1]
(ii) Mark the water levels in the U-tube in
Diagram 5.3 while air flows.
[1]
3.
Diagram 2 shows a cross-section of a spoiler
which is attached to a racing car. The aerofoil
shape of the spoiler produces a downward
force when air flows through it.
………………………………………………………………
………………………………………………………………
[2 m]
(ii) Compare the air pressure above and
below the paper when air is blown.
………………………………………………………………
[1]
(iii) Relate the speed of the air to the
pressure of the air.
………………………………………………………………
………………………………………………………………
[1]
(a) Name the principle involved in producing the
downward force.
………………………………………………………………
[1 mark]
(b) Explain how the spoiler functions.
………………………………………………………………
………………………………………………………………
………………………………………………………………
(c) The area of the upper surface of the spoiler is
0.25 m2. The pressure at the upper surface of
the spoiler is 1500 Pa and the pressure at the
lower surface is 500 Pa.
Calculate
(i) the difference in pressure between the
upper and lower surfaces of the spoiler.
[1 mark]
(b) Diagram 11.2 shows four design of perfume
sprays, P, Q, R and S with different
specifications. You are required to determine
the most suitable design of a perfume spray
to produce a fine spray. Explain the
suitability of each aspect and then determine
the most suitable design of a perfume spray.
Give reason for your choice.
[10 marks]
(ii) the downward force acting on the spoiler
due to the difference in pressure in 2(b)(i).
[2 marks]
(d) Give one reason why a downward force is
needed when the racing car is moving fast.
………………………………………………………………
[1 mark]
4. Section B
An aeroplane with mass of 3.6 x 105 kg and total
surface area of 460 m2 is at a constant height.
The resultant force acting on the aeroplane at that
moment is zero.
(i) Calculate the weight of the aeroplane.
[1 mark]
(ii)
Determine the lifting force acting on the
aeroplane.
[1 mark]
(iii) Based on the answer in 11(b)(ii),
calculate the pressure difference
between the upper and lower surfaces
of the wings of the aeroplane.
5. Section C
(a) Diagram 9.1 shows a cross section of a wing
of
a moving aeroplane. The wing of the
aeroplane experiences a lift force.
[3 marks]
(i)
Name the shape of the cross-section in
Diagram 9.1.
(ii)
Explain why the lift force acts on the wing
of the aeroplane.
[4 marks]
(b)
Two ski jumpers ski down from a very high
platform with the same take off velocity.
Diagram 9.2 and Diagram 9.3 show the
posture of the two ski jumpers during take
off from the platform. Diagram 9.4 and
Diagram 9.5 show the posture of the two ski
jumpers in the air. They land on the ground
at the same instant.
6. Section C
Diagram 9.1 and Diagram 9.2 show two toy boats
are separated at two different distances to each
other due to the difference in pressure. In
Diagram 9.1, the end of the rubber hose is
pressed to reduce the size of the hose nozzle.
getah dipicit untuk mengurangkan saiz muncung hos.
Diagram 9.1 / Rajah 9.1
(i)
Based on Diagram 9.2 and Diagram 9.3,
compare the posture of the two ski jumpers.
[1
mark]
(ii) Based on Diagram 9.4 and Diagram 9.5,
compare the landing distance of the two ski
jumpers.
[1 mark]
(iii) Based on Diagram 9.4 and Diagram 9.5, relate
the lift force to the landing distance.
[2 marks]
Diagram 9.2 / Rajah 9.2
(a)
[1 mark]
(b)
(iv) Name one spot which uses the same principle
of lift force as the ski jumper. Explain the
similarities.
[2 marks]
(c)
What is the meaning of pressure?
(i) Using Diagram 9.1 and Diagram 9.2,
compare the speed of water spurting out
from the rubber hose and the distance of
separation between the toy boats.
[2 marks]
(ii) State the relationship between the speed of
water spurting out and the distance of
separation between the toy boats to make a
deduction regarding of relationship
between the speed of water and pressure.
[2 marks]
Diagram 9.6 shows a sailboat.
(iii) Name the physics principles involved.
[1 mark]
(c)
You are required to give some suggestions
to design a sailboat which can travel faster.
Using the knowledge on motion, forces and
the properties of materials, explain the
suggestions based on the following aspect:
(i)
the surface of the board
(ii)
the shape of the board
(iii)
material used for the board
(iv)
material used for the sail
(v)
the size of the sail
[10 marks]
Diagram 9.3 shows a cross section of a
Bunsen burner.
.
Diagram 9.3 / Rajah 9.3
Using the physics principle, explain how a
complete combustion can be produced by
the Bunsen burner.
[4 marks]