FORM 2 CHAPTER 8 FORCE AN MOTION

Unit = Newton meter (Nm).



The Principle Of Levers

Load(N) x The distance of load = Force or x The distance of
from the fulcrum (m) effort from the
Effort(N) fulcrum (m)

Example of the principle of lever

1. What effort is required to keep the lever in balance?

Load(N) x The distance of L = xForce or The distance of E
from the fulcrum Effort(N) from the fulcrum
2N (m)
E (m)
x 30cm
x 50 = E x 50cm

E = 60

= 60 / 50
= 1.2N

Example of the principle of lever

2. Calculate the weight of the load.

Load(N) x The distance of L = xForce or The distance of E
from the fulcrum Effort(N) from the fulcrum
L (m)
L (m)
x 40cm
x 40 = x4N 100cm

L = 400

= 400/ 40
= 10N



Example of the principle of lever

A) B)

The distance of L Force or The distance of E
from the fulcrum Effort(N) from the fulcrum
x = xLoad(N)

(m) (m)

Example of the principle of lever

A)

Wx 80cm = x10N 60cm

xW 80 = 600
= 600/ 80
W = 7.5N

Example of the principle of lever

B)

x40N 45cm = xY 50cm

xY 50 = 1800
= 1800/ 50
Y = 36N

C) D)

The distance of L Force or The distance of E
from the fulcrum Effort(N) from the fulcrum
x = xLoad(N)

(m) (m)

C)

x250g 35cm = x500g Qcm
Qx
500 = 8750
Q = 8750/500
= 17.5cm

D)

x =E 75cm x195N 25cm
E=
x195 25
E=
75

65N

Exercise
1. calculate the weight of Ali needed to keep the see-saw
in balanced if the weight of Abu is 280 N.

Ali Abu

Ali x 2.5m = 280N × 1.5cm
Ali = 280 x 1.5
2.5
L = 168 N

MODUL SAINS (pg 131)
The diagram shows a force of 5 N applied to a screwdriver
handle to open a tin lid.
What is the load of the screwdriver?

Load × Load distance = Effort × Effort distance
L x 2cm = 5N × 28cm
L = 5 × 28
2

L = 70 N

MODUL SAINS (pg 131)

Determine the effort needed to push the load inside the
wheelbarrow.

1kg = 10N

Load × Load distance = Effort × Effort distance
E x 2m = 45kg × 0.5cm
E = 45 × 0.5
2
E = 11.25kg

E = 11.25 x 10
= 112.5N

Pressure

A continuous physical force exerted
(dikenakan/用力） on an object.







Pressure

Application of Pressure
Small surface area, high pressure:

Application fo Pressure
Large surface area, small pressure:



Exercise of Pressure:
ANSWER:

1kg = 10N

Force = 62 x 10 Surface area = 0.075m2
= 620N

Pressure = 620
0.075

= 8266.67Pa



Exercise



AIR PRESSURE

Produces when the air around
us presses on the surfaces of

the objects that are in it.

KINETIC THEORY OF GASES

• The gas particles move freely in all directions.
• The particles continuously hit the walls of the

container and bounce back.
• A force is exerted by the particles on the walls of the

container.
• This force produces a pressure on the walls of the

container.

AIR PRESSURE

2 FACTORS THAT AFFECT AIR PRESSURE:

1. Volume (of container)
2. Temperature

FACTORS AFFECTING AIR PRESSURE IN A
CLOSED CONTAINER

FACTOR RELATIONSHIP EXPLANATION
Volume
Volume decreases, • The air particles
Air pressure
increases move in a smaller

space
•More particles hit the

walls of container
•Larger force is

produced
•Higher pressure acts
on the wall

FACTORS AFFECTING AIR PRESSURE IN A
CLOSED CONTAINER

FACTOR RELATIONSHIP EXPLANATION

1. Volume Volume decreases, • The air particles
Air pressure move in a smaller
increases space
•More particles hit the
walls of container

1. The reading on the bourdon gauge increases when the syringe is
pushed.

2. the reading on the Bourdon gauge decreases when the syringe is
pulled.

3. as the volume increases, the air pressure decreases.



FACTOR RELATIONSHIP EXPLANATION

Temperature Temperature •Air particles move
increases, faster
Air pressure •More particles hit the
increases walls of container
•Larger force is
produced
•Higher pressure acts
on the wall

1. The reading of Bourdon gauge shows the
total pressure in that container.
2. as the temperature increases, the air
pressure increases.



Atmospheric pressure

• Meaning: the pressure exerted by the
atmosphere on the surface of the Earth and all
object on the Earth.

PRINCIPLE OF AIR PRESSURE

Air will flow from a region of higher air
pressure to a region of lower air pressure.
This movement of air is caused by a force
acting in the direction of higher to lower air
pressure.

PRINCIPLE OF AIR PRESSURE

If a surface lies between two regions of different
air pressures, a force will act on the surface in
the direction of higher to lower air pressure.

APPLICATION OF THE
PRINCIPLE OF AIR PRESSURE

1)SYRINGE

 When the piston is pulled
upwards, the volume of
air in the barrel increases.

 The air pressure in it is
reduced.

 The higher outside
pressure forces the water
through the needle into
the barrel

2)SYPHON

 The bent tube is filled with water (syphon) has
low pressure in it.

 The higher outside pressure pushes the water
into the tube.

 The water flows out of the tube

3)DRINKING STRAW

 Sucking removes the air inside the straw
producing low pressure.

 The higher pressure outside pushes the water
into the straw.

4)POURING MILK FROM CAN

 When the milk flows out of the can, the pressure
inside the can is reduced.

 The second hole allows air to enter the can and fill
up the empty space producing equals air pressure
inside and outside the can.

 The equal pressure enable the milk to flow
continuously out of the can.

5)PLUNGER

6)VACUUM CLEANER

Relationship between Altitude and
Atmospheric Pressure

Higher altitude  lower air pressure.
Lower altitude  higher air pressure.