The document summarizes Newton's three laws of motion: 1) The first law of inertia states that an object at rest stays at rest and an object in motion stays in motion with the same speed and direction unless acted upon by an unbalanced external force. Inertia is directly proportional to mass. 2) The second law of acceleration says that acceleration is directly proportional to the net force acting on an object and inversely proportional to its mass. 3) The third law of action and reaction says that for every action force there is an equal and opposite reaction force.

1. GOOD MORNING GRADE 8!
JESUS LOVES YOU <3

2. MOST ESSENTIAL LEARNING COMPETENCY
Investigate the relationship
between the amount of force
applied and the mass of the
object to the amount of
change in the object’s motion

3. What is the Exact
Relation Between
FORCE AND MOTION?

4. VERSUS
Aristotle Galileo
“The natural State of a body is to remain at rest and
a force has to act on a body for it to move and to
keep it moving.”
“The natural tendency of a moving object is to
continue moving and no force is required to keep it
moving.”

5. Newton’s
Three Laws of
Motion
Science 8

6. 1. Law of Inertia

7. MASS AS A MEASURE OF INERTIA

11. Mass and Weight
 On Earth, Mass and Weight is
directly proportional to each other. If
the mass is high, its weight is also
big. If the mass is halved, the weight
is also halved. But, this does not
mean that mass and weight are the
same.

12. Mass and Weight
For an instance, the
gravitational pull of earth acts
on an object that has mass,
then the combined quantity is
called weight.

13. Weight (w) = mass (m) x gravity (g)
w = mg

14. SI Unit of
Weight
Mass Earth’s
Gravity
Kilogram
meter/second
^2 (kg m/s^2)
or Newton
Kilogram (kg) 9.8
meter/second
^2 (m/s^2)

15. Sample Problem:

16. SUMMARY OF THE FIRST LAW
 The first law of Newton, the law of inertia, states that
a stationary object remains to be at rest, or an object
moving at a constant velocity continues to be moving
at constant speed and direction unless imposed by
an external force that gives a net unbalanced force.
 Inertia is measured by the amount of mass that the
object possesses. (The greater the mass, the greater
the inertia.)
 Weight is the product of mass and gravity.

17. Practice Exercise.
A 1.0 kg object is brought to planet Mercury
where the acceleration due to gravity is 0.38
times its value on Earth.
a.) What is the weight of the object on Earth?
b.) What is the mass of the object on
mercury?
c.) What is its weight on Mercury?

18. LAW OF ACCELERATION

19. FORCES of varying types,
when they are imposed and
caused an unbalanced state
to an object, always results in
ACCELERATION.

20. LAW OF ACCELERATION
 Investigates the relationship
of force and mass in the
object’s acceleration.
ACCELERATION
Directly related
with net force
Inversely related
with net force
Unbalanced forced result in a Net
Force that leads to

21. “The DIRECTION OF THE NET
FORCE D and
ACCELERATION are THE
SAME, and both are DIRECTLY
related, while ACCELERATION
and MASS are INVERSELY
related.
LAW OF ACCELERATION

22. Mathematical equation of the
Law of Acceleration
Acceleration = net force
mass
a = Fnet / m

23. Often rearranged as:
Fnet = ma

24. Sample Problem:
Suppose a ball of mass
0.60 kg is hits with a force
of 12 kg m/𝑠2
. What will
be its acceleration?

25. Practice Exercise
If a bowling ball with a force
of 15.0 kg m/𝑠2
acts on a
bowling pin with 5.0 kg
mass, what will be the
acceleration?

26. LAW OF ACTION & REACTION

29. An object of
Weight 30 N
rests on a table.
(a) What are the
forces acting on
the object? (b)
What are the
reactions to
these forces?

30. Practice Exercise
A ball hangs from the
ceiling by means of a
thread of negligible weight.
Enumerate all the action-
reaction forces.