FORCES AND MOTION MODULE

8
Science
Quarter 1 – Module 1:
Forces and Motion
A Requirement for EDUC403
Educational Technology and Instructional Material Development
MA in Educational Management

Science – Grade 8
Quarter 1 – Module 1: Forces and Motion
First Edition, 2020
This module is crafted as a requirement for the subject 403, Educational Technology
and Instructional Material Development, for MA in Educational Management. In accordance
to Republic Act 8293, section 176, no parts of this module will be used without the consent of
the author or without proper citation. You may contact the author if you intend to use any part
of this material.
Development Team of the Module
Author: Jenny Grace C. Capuno
Editor: Cristina S. Magpantay
Reviewer: Jesse M. Geron
Layout Artist: Jenny Grace C. Capuno
Proofreader: Harold I. Inciong

Science
Quarter 1 – Module 1:
Forces and Motion
8

Introductory Message
For the facilitator:
This module is designed as supplemental material for understanding the relationship
between forces and motion. This contains activity sheets and will be used to evaluate
student’s learning competencies. Instruct learners to use separate sheets in answering the
pre-test, self-check exercises, and post-test. Accomplished activities and exercises will be
submitted to the subject teacher on or before the given schedule. It should also be noted that
parents should monitor the progress of their child’s learning.
For the learner:
This module is designed to guide you in understanding the concepts of force and
motion. All parts of this module are important, so make time to read everything for you to
easily answer the activities. Make sure that you write your answer in your quiz notebook and
submit it on or before the due date. Do not leave unanswered activities. If you have
questions and clarifications, communicate with your subject teacher.
Good luck and enjoy learning!

What I Need to Know
This module is designed to help you master the concepts of Force and Motion. The
scope of this module allows you to use it in many different learning situations. This learning
material provides you with an overview of forces that will lead to a better understanding of:
Lesson 1 – Three Laws of Motion
After exploring this module, you are expected to:
1. understand the concept of force and its relation to motion
2. differentiate balanced and unbalanced forces
3. infer the relationship between the amount of force applied and the mass of the object
to the amount of change in the object’s motion
4. recognize the different laws of motion in everyday activities
5. summarize learnings about the three laws of motion

What I Know
Choose the letter of the best answer. Write the letter on a separate sheet of paper.
1. A book is resting on your table. Which statements below best describe the situation?
a. No forces acting on the book.
b. Your book pushes on the table only.
c. The table pushes on your book only
d. The forces acting on the book are balanced.
2. Which force always pulls downward on objects?
a. Friction force
b. Applied force
c. Gravity
d. Air resistance
3. A change to the motion of an object is caused by _____.
a. Balanced forces
b. Unbalanced forces
c. Acceleration
d. Velocity
4. Which of the following is an example of unbalanced force.
a. an arm wrestling where there is no winner
b. a tug of war where the rope doesn’t move.
c. a girl sitting on a chair.
d. a boy pushing a cart.
5. Two students are pushing a table in the opposite direction. Student A exerts 15N
force to the right, while student B applies 25N force to the left. Which direction will the
box move?
a. upward
b. downward
c. to the left
d. to the right
6. According to the first law of motion, why is it important to wear seatbelt when
traveling in vehicles?
a. It acts as an unbalance force that will stop you from being in motion.
b. It stops vehicular accidents.
c. It is required by law.
d. It makes you comfortable when sleeping while traveling.
7. What happens to acceleration of an object if you increase the mass?
a. the acceleration increases

b. the acceleration decreases
c. the acceleration will remain the same
d. the object will stop
8. Two grocery shoppers are pushing two carts with 10 kg of items each. Shopper A
exerts force of 15 N, while shopper B exerts 10 N. Which of them will reach the
counter first?
a. Shopper A
b. Shopper B
c. both Shoppers A and B
d. neither Shopper A nor B
9. A boy pushing a 10 kg box is accelerating at 5 m/s 2 . How much force is needed to
push the cart?
a. 20 N
b. 30 N
c. 40 N
d. 50 N
10. Which law of motion states that for every action, there is equal and opposite
reaction?
a. Law of Inertia
b. Law of Acceleration
c. Law of Action-reaction
d. Law of Gravity

LESSON 1
NEWTON’S THREE LAWS OF MOTION
In this lesson, you will differentiate the three laws of motion and how they affect the
motion of an object. You will also get familiar with the vocabulary terms associated in this
lesson.
What’s In
In Grade 7, you learned about motion in terms of displacement, speed, velocity, and
acceleration. Most motions that we encounter in our daily activities are caused by FORCE.
This module will teach you the effects of force on motion.
Notes to the Teacher
Provide students with an overview by discussing the different
types of forces. Students must have a clear understanding of forces
acting on objects before proceeding to the main concept.

What’s New
What is force?
Force is defined as push or pull acted on an object. There are two classifications of
forces: contact force and non-contact force.
Contact forces are forces which involve two objects physically interacting or touching
each other.
Non-contact forces are forces that act between two objects that do not require
physical interaction.
Types of forces
The table below explains and illustrates the different types of forces.
CONTACT FORCES
1. Air-resistance force
The force acting on objects traveling on air.
EXAMPLE ILLUSTRATION
2. Tension force
The force transmitted along a string, cable,
rope, or a wire when pulled by an object to the
opposite side of the string.
3. Spring force
The force exerted by a stretched or compressed
spring on an object that is attached to it.
4. Normal force (reaction)
When one force is exerted on another body (A),
the second body (B) exerts force perpendicular
to the surface of the first body (A).
5. Applied force
The force exerted by an object or a person (A)
to another object (B) by physical contact.
Normal force acting
on the vase (A)
Normal force acting
on the table (B)

6. Friction force
The force that resists the sliding or rolling of one
object (A) over the other (B).
NON-CONTACT FORCES
1. Gravitational force
The force that attracts any object with mass.
Fgrav = m * g
Where:
g = 9.8 N/kg (on Earth) and
m = mass (in kg)
2. Electrical force
The force exerted between two charged bodies.
EXAMPLE ILLUSTRATION
3. Magnetic force
The force of attraction or repulsion between
electrically charged particles due to motion.
What Is It
Sir Isaac Newton was one of the most prominent scientists of all time. His
ideas became the foundation for modern physics. During the summer of 1665 and the spring
of 1667, Isaac Newton made two long trips to his hometown, Woolsthorpe, to escape the
plague spreading in Cambridge. The bubonic ‘Great Plague’ of 1665–1966 was the worst
epidemic in England after the black death of 1348. By 1666, Newton had submitted the
blueprints for his three laws of motion. After twenty years, he presented his three laws of
motion in the book, "Principia Mathematica Philosophiae Naturalis."
NEWTON’S FIRST LAW OF MOTION
The 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 in the same direction unless acted upon an external force.

To illustrate:
It means that the object keeps doing what it does. This tendency is called inertia.
Inertia is the tendency of an object to resist change in its state of motion. Galileo discovered
the concept of inertia in the seventeenth century. Based on his experiment, if there is no
inertia, an object will move in a constant speed.
Remember:
The bigger the object has a greater tendency to resist changes in its state of motion.
Between a golf ball and a bowling ball, a bowling ball is more difficult to move.
The motion of an object may be caused by two kinds of forces: Balanced and
unbalanced forces. The table below explains the two forces briefly.
BALANCED FORCE
UNBALANCED FORCE
- Equal in magnitude - Unequal in magnitude
- Opposite direction
- Can be the same or opposite
direction
- Causes no change in the
speed of the object
- Causes change in speed and
direction
- Net force is equal to zero - Net force is not equal to zero

Examples:
Examples:
Net force is the sum of all forces acting on an object. If net force is equal to
zero (F net = 0), the force is balanced, therefore, objects will not move.
NEWTON’S SECOND LAW OF MOTION
The Law of Acceleration states that:
The acceleration of an object is directly proportional to the magnitude of the net
force acting on it and inversely proportional to its mass.
This means that the acceleration is always in the same direction as the net force. This is
express mathematically as F net = ma.

This means:
• Objects with lighter mass will accelerate more than the heavier mass.
• More force moving an object, the more the object will accelerate.
• If force is increased, acceleration increases.
• If mass is increased, acceleration decreases.
CALCULATING SECOND LAW OF MOTION
Newton’s second law is best described with a mathematical equation that relates
three variables, force, acceleration and mass to one another. The equation can be stated in
three forms:
F = m x a m = F / a a = F / m
Mass is defined as the quantitative measure of inertia, a fundamental property of all
matter. Acceleration on the other hand, is the rate of change of the velocity of an
object with respect to time. The unit of force is Newton (N); mass is kilogram (kg);
acceleration is meter per second squared (m/s 2 )
Example #1: A 2 kg object accelerated at a constant speed of 5 m/s 2 . How much force is
needed to accelerate the object?
Given: 2 kg, 5 m/ s2
Required: Force
Equation: F = m x a
Solution: F = 2kg x 5 m/s 2
Answer: F = 10 kg/m/s 2 or 10 N
Conversion
1
kg
m/s 2 = N

Example #2: A 10 N force is applied to an object with a mass of 2 kg. What is the
acceleration of the object?
Given: 10 N, 2kg
Required: Acceleration
Equation: a = f/m
Solution: a = 10 N / 2kg
Answer: a = 5 m/s 2
Conversion:
10 N 10 kg●m/s 2
2 kg = 2 kg
NEWTON’S THIRD LAW OF MOTION
The Law of Action-Reaction states that:
For every action, there is an equal and opposite reaction.
This means that:
In every interaction, there is a pair of forces acting on the two interacting
objects in different directions.
The size of the forces on the first object equals the size of the force on the
second object.
Forces always come in pairs - equal and opposite action-reaction force pairs.
Action and reaction acts on different bodies.
Examples:
A variety of action-reaction force pairs are observed in our environment. Think about the
fish swimming through the water. A fish uses its fins to push water backwards. But a push
on the water will just make the fish accelerate. Below are other examples.

What’s More
Experiment #1: Law of Inertia
Egg Drop
Objective:
At the end of this activity, students will be able to understand how inertia works.
Materials Needed:
Glass with water
Boiled egg
Cardboard (thick)
Toilet paper cardboard
Procedure:
1. Place the cardboard on top of the glass
2. Place toilet paper roll vertically in the middle of the cardboard
3. Balance egg on top of the toilet paper roll so the egg is lying on its side. Refer
to the illustration above.
4. Once everything is balanced on top of each other, with one swift and quick
motion hit the side of the cardboard with your hand. Put enough force to push
the cardboard off the glass.
Q1. What happens to the egg?
Q2: How does inertia work on this experiment?
Q3. In your activity notebook, draw the outcome of the experiment. (5 points)

Experiment #2: Law of Acceleration
Objective:
Toy Truck Experiment
At the end of this activity, students will be able to understand relationship of mass
and acceleration.
Materials Needed:
Toy truck (dump truck)
Small rock (same size and weight)
Ramp
Meter stick, ruler or tape measure
Stop watch
Procedure:
1. Construct a simple ramp 18 inches high and about 24 inches long using a
piece of thick cardboard.
2. Place a toy truck at the top of the ramp.
3. Release it and measure how far it rolls.
4. Put three pieces of small rocks.
5. Release the toy truck and measure how far it goes. Record your distance
and time observation.
6. Repeat the experiment with six rocks, then nine rocks.
Q1. What happens to the acceleration of the truck when you increase the
rocks?
Q2: What is the relationship of mass to the acceleration of an object?
Q3: Which attempt has the longest distance? Why?
Record your observation in your activity notebook.
No. of
Attempts
Distance (meters)
Time (seconds)
1
2
3

Experiment #3: Law of Action-Reaction
Objective:
Balloon and Rockets
At the end of this activity, students will be able to understand the third law of
motion by assimilating the action of a balloon to a rocket.
Materials Needed:
Balloons
5 m. string
Tape
Straw
Procedure:
1. Insert one end of the string through the straw.
2. Tie the string to stationary (still) objects on opposite sides of the room. Make
sure to stretch the string tight.
3. Blow up the balloon and hold it tight. Air should not escape but don’t tie it.
4. Ask someone hold the balloon under the straw and tape the balloon to the
straw in two places.
5. Let go of the balloon and observe as it propel like a rocket.
Q1. What happens when you let go of the balloon?
Q2: What are the forces acting on the balloon?
Q3: Identify the action and reaction acting on the balloon. In you activity
notebook, draw the activity and use arrow representing action and reaction (5
points).

What I Have Learned
1. Forces acting on an object may be contact and non-contact force.
2. When a balanced force acts on an object, it causes no change in the object’s motion.
When an unbalanced force is acted on an object, it will move, change in speed, or
direction.
3. It was Galileo who pioneered the concept of inertia, while Sir Isaac Newton
formulated the laws of motion.
4. Newton’s three laws of motions are Law of Inertia, Law of Acceleration and Law of
Action-reaction, respectively.
5. According to Law of Inertia, the greater the mass of an object, the higher the inertia.
6. Law of acceleration -s mathematically expressed as F = m●a. The acceleration of an
object depends directly upon the net applied on the object, and inversely
proportional to the mass of the object.
7. If the force applied on an object is increased, the acceleration of the object is
increased, too. However, if the mass of an object is increased, the acceleration of
the object is decreased.
8. According to the Law of Action-reaction, the magnitude of the forces applied on the
first object equals the magnitude of the force on the second object. The direction of
the force on the first object is opposite to the direction of the force on the second
object.
9. The concept of the three laws of motion can be summarized through this diagram:
Diagram adapted from https://www.sas.upenn.edu/~kennethp/nkdievid2.pdf

What I Can Do
Activity 1. Understanding Science Words
Learning the Skill: Solving Crossword Puzzle
Directions: Identify the word using the clues provided.
Activity 2. Concept Check
Directions: Study the concepts of three laws of motion, then answer the following questions.
1. Which law is associated with inertia?
____________________________________________________________
2. What will happen to the acceleration if you increase the force applied to the object?
____________________________________________________________

3. What will happen to the acceleration if you apply the same force to an object with
lesser mass?
____________________________________________________________
4. Which law states that force is dependent on the object’s mass and acceleration?
____________________________________________________________
5. Which law is also known as the action-reaction?
___________________________________________________________
6. If the forces are balanced, what is the resulting acceleration?
___________________________________________________________
7. What is the net force if you push a table to the left with 10N of force and a friend
pushes the table to the right with 10N of force?
___________________________________________________________
8. What is the net force if you start to pull instead of pushing in #7?
____________________________________________________________
9. What will happen to the acceleration if you double the mass of an object while leaving
the net force the same?
_____________________________________________________________
10. A Toyota Grandia with a mass of 2,200 kg exerts 2500 N. What is the van’s
acceleration?
_____________________________________________________________

Additional Activities
Activity 3: Inertia and Moving Objects
Consider a man driving with a cup filled with coffee on his side. As
he accelerates, the cup of coffee moves to the same direction with the car.
When the driver suddenly hits the break, the coffee continues to move
forward. Because of sudden change in motion, the coffee spills. With this
concept in mind, answer the following questions in your activity notebook.
1. What happens to the driver’s motion while the car is running?
2. What will happen to driver’s motion if the man suddenly steps
the break?
3. Why is it important to wear a seatbelt when traveling on a
vehicle?
4. What does the law of inertia state?
Activity 4: Mass and Acceleration
Suppose a jeep and a tricycle traveling from opposite directions collide with each
other. Both accelerate at the same speed. Anticipate the outcome of the scenario and
answer the following questions?

1. Which vehicle do you think will be thrown farther?
2. Which vehicle has greater mass?
3. What is the relationship between the mass and motion of an object?
4. Based on the concept of mass and acceleration, which one will acceleration
faster.
5. What is the relationship of mass and force and their effect to motion?
6. Calculate the force required to move an 86 kg tricycle with 5.5 m/s
acceleration.
Activity 5: Action-Reaction
Observe how the law of motion acting on clothes hanging on the clothesline. Answer
the questions below.
1. Which Newton’s law of motion is displayed in the picture?
2. What are action and reaction forces acting on them?
3. Why do you think clothes are not falling or touching the ground?
4. Does the example shows a balanced or unbalanced force?
5. What does the third law of motion state?

Activity 6: Forces and Motion Daily
Directions: The examples show forces and motion in our daily activities. In the first column,
identify if the force acting on an object is BALANCED or UNBALANCED. Write N/A if the
statement does not show any of them. In the second column, determine the law of motion
stated. Write FIRST LAW, SECOND LAW, THIRD LAW in the box provided.
ACTIVITIES
1. Exerting force to raise the flag on a pole.
BALANCED
OR
UNBALANCED
FIRST LAW,
SECOND LAW,
THIRD LAW
2. A driver of a bus, hit the brake suddenly and, by
inertia, shoots forward because he’s not wearing
a seatbelt
3. A rolling ball does not stop moving by itself.
4. The hammer strikes a nail, and the nail goes
deeper into the wood. The hammer makes a
backward movement when it hits the nail hard.
5. A book on a table is in a state of rest.
6. When rowing a boat, the water is pushed
backward with the paddle and then reacts by
pushing the boat in its opposite direction.
7. When two people pull the opposite sides of the
same rope, and it stays at the same point,
8. A golfer must exert force in order for his ball to hit
the hole.
9. A rocket needs to acquire a certain speed in
order to be able to go into orbit.
10. The calculation of the force required to push a
box.

Assessment
Part I. Choose the letter of the best answer. Write the letter on a separate sheet of paper.
1. Which statements below best describe the forces acting on a book resting on a table?
a. No forces acting on the book
b. The book pushes on the table only.
c. The table pushes on your book only
d. The forces acting on the book are balanced.
2. Which force always pulls downward on objects?
a. Applied force c. Air resistance
b. Friction force d. Gravity
3. What causes the change in the motion of an object?
a. Acceleration c. Unbalanced forces
b. Balanced forces d. Velocity
4. Which of the following is an example of unbalanced force.
a. an arm wrestling where there is no winner
b. a boy pushing a cart forward.
c. a girl reading while sitting on a chair.
d. a tug of war where the rope doesn’t move.
5. Two students are pushing a table in the opposite direction. Student A exerts 25N
force pull to the left, while student B applies 15N force push to the left. Which
direction will the box move?
a. downward c. to the right
b. to the left d. upward
6. According to the first law of motion, why is it important to wear a seatbelt when
traveling in vehicles?
a. It acts as an unbalanced force that will stop you from moving.
b. It prevents vehicular accidents from happening.
c. Sleeping is more comfortable while traveling.
d. Wearing a seatbelt is required by law.
7. What happens to acceleration of an object if you decrease the mass?
a. the acceleration decreases c. the acceleration will remain the same
b. the acceleration increases d. the object will stop

8. Two grocery shoppers are pushing two carts with 10 kg of items each. Shopper A
exerts force of 15 N, while shopper B exerts 10 N. Which of them will reach the
counter first?
a. Shopper A c. both Shoppers A and B
b. Shopper B d. neither Shopper A nor B
9. A horse pulling a 10 kg cart is accelerating at 25 m/s 2 . How much force is needed to
push the cart?
a. 150 N c. 350 N
b. 250 N d. 450 N
10. Which law of motion states that for every action, there is equal and opposite
reaction?
a. Law of Gravity c. Law of Acceleration
b. Law of Inertia d. Law of Action-reaction
Part II. Summarize the concept of Three Laws of Motion. Choose from ANY of the following
output.
a. Write an essay with ten (10) or more sentences.
b. Illustrate the concepts of motion by using graphic organizers.
c. Create a poster featuring the three laws of motion.
d. Record a vlog about the summary concepts of motion. Video must be less than 3
minutes.
Criteria
Exceeds Standards
(3)
RUBRIC
Meets Standards
(2)
Almost Meet
Standards (1)
Content
The sentences are
aligned with the topic.
The flow of thought is
consistent throughout.
The flow of thought
is aligned with the
topic, but with
inconsistencies.
There is an obvious
attempt to express a
consistent thought.
Creativity
The ideas and style
are refreshing and
imaginative.
Express some new
and imaginative
ideas.
Shows creative
ideas, but mostly
uninspired.
Organization
Organization and use
of supporting details
evident in the work.
Organization and
use of supporting
details sometimes
evident in the work.
Attempt to use
organization of
supporting details
evident in the work.

Answer Key
What I Know
1. D
2. C
3. B
4. D
5. C
6. A
7. B
8. B
9. D
10. C
Assessment
1. D
2. D
3. C
4. B
5. B
6. A
7. B
8. A
9. B
10. D
What's More
Activity #1
Across
1. Motion
3. Air resistance
4. First Law
5. Magnetic
7. Applied
11. Friction
Down
1. Gravity
6. Third Law
8. Spring
9. Net Force
10. Mass
11. Tension
14. Force
15. Motion
Activity #2
1. First Law
2. Acceleration will increase
3. Acceleration will increase
4. Second Law
5. Third Law
6. Zero
7. Zero
8. The Net force will be 20N. The table will move to the left
9. The acceleration will decrease
10. Acceleration: 1.136 m/s 2
Additional Activities
Experiment #1
1. The egg falls into the water.
2. Inertial keeps the egg on top of
the cardboard roll.
3. Draw answer #1
Experiment #2
1. Acceleration decreases
2. The greater the mass, the lesser
the acceleration
3. First
Experiment #3
1. The balloon propels to the
opposite side.
2. Applied force and air resistance
3. Action: the balloon releases air,
Reaction: the balloon propels
forward
Activity #3
1. The driver’s motion goes along
with the car.
2. The driver will continue to move
forward.
3. The belt acts an unbalanced
force that keeps the driver from
being in motion.
4. The object in motion will remain
in motion and an object at rest
will stay at rest unless acted by
an unbalanced force.
Activity #4
1. The tricycle will be thrown farther
2. The jeep
3. Mass is inversely proportional to acceleration.
Meaning, more mass = less acceleration = less
motion
4. The tricycle
5. If the force applied is greater, the acceleration of
the object with less mass will increase.
6. 473 N
Activity #5
1. Law of action-reaction
2. Gravity and tension force
3. The tension force keeps the clothes on their place.
The force applied by cloth pins work, too.
4. Balanced force
5. For every action, there’s an equal and opposite
reaction.
Activity #6
1. Unbalanced – Third
2. Unbalanced – First
3. Unbalanced – First
4. Unbalanced – Unbalanced – Third
5. Balanced – First
6. Unbalanced – Third
7. Balanced – Third
8. Unbalanced – Second
9. Unbalance – Second
10. N/A - Second

References
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https://byjus.com/physics/balanced-force/.
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it Works:,into the glass of water.
"Mechanics: Physics Aboout." Physicsabout. https://physicsabout.com/category/mechanics/.
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“Newton's Laws of Motion.” Reading, n.d.
https://www.sas.upenn.edu/~kennethp/nkdievid2.pdf.
Schnotz, Wilhelm. "Second Law of Motion Experiments." Sciencing. March 02, 2019.
https://sciencing.com/second-law-motion-experiments-6952612.html.
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Cambridge.