SCIENCE FORM 2 CHAPTER 8 (8.1)

CHAPTER 8
FORCE AND MOTION

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Content

8.1 Force
8.2 EFFECT OF FORCE

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What is force ?

1.Push and pull upon an object.
2. Measurement of force: spring balance
3. Unit of force: Newton (N)

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Types of forces

1. Frictional force
2. Gravitational force
3. Normal force
4. Buoyant force
5. Weight
6. Elastic force

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Frictional force

• The force that resists the movement
between two surfaces that are in contact
with each other.

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Buoyant force

• The thrust force
acting on an object
that is floating on the
surface of a fluid.

DRAW!!!

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Elastic force

• Exist when a material is stretched or
compressed.

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Normal force

• The force produced when an object is in
contact with surface.

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The weight

• The weight of an object is defined as the
gravitational force acting on it

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Gravitational force

• The force of attraction that causes objects
to falls towards the Earth.

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Weight Vs Gravity

• The weight of an object
depends on the pull of gravity

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Characteristic of Force

• Force is a vector quantity that has
magnitude and direction.

• A force can be measured using a
spring balance.

• The unit of force is Newton (N).

1kg = 10N
100g =1N

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Action-reaction Pair

• Newton’s Third Law states that every action force,
there is a reaction force of the same magnitude but
in the opposite direction.

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EXAMPLES:
Two Trolley Compressed

Action Firctional
Force Force

DRAW!!!

Trolley A Trolley B
Exert elactic force Exert elactic force
(action force) to the (reaction force) to the

trolley B trolley B

EXAMPLES:
Two Trolley Launched

Firctional Action
Force Force

DRAW!!!

• Trolley A move to the left while Trolley B

move to the right
• Both Trolley move in the same distance